SELYA, Circuit Judge.

In plaintiffs' judgment, Splendorform International, Inc. (Splendorform), a lingerie manufacturer, made a slip when it laid off some ninety sewing machine operators incident to a reorganization in 1984. At a much later date, thirty-eight of these disaffected former employees brought suit against both their union, the International Ladies' Garment Workers' Union-Puerto Rico Council (ILGWU), and their quondam employer, Splendorform, in federal district court. The action comprised a classic hybrid § 301/unfair representation amalgam; the combination claim asserted that, on the one hand, plaintiffs' employer had breached § 301 of the Labor Management Relations Act (LMRA), 29 U.S.C. § 185, by violating a collective bargaining agreement, and that, on the second hand, their union had ignored the duty of fair representation implied under the National Labor Relations Act (NLRA), 29 U.S.C. § 151 et seq., with regard to the company's breach of contract. See generally DelCostello v. International Brotherhood of Teamsters, 462 U.S. 151, 163-66 nn. 14-16, 103 S.Ct. 2281, 2289-92 nn. 14-16, 76 L.Ed.2d 476 (1983) (discussing characteristics of § 301/unfair representation hybrids). The district court granted summary judgment in favor of both defendants. Arriaga v. ILGWU, 656 F. Supp. 309 (D.P.R. 1987). This appeal followed.

I. FOUNDATION

The relevant factual and procedural background has been set out authoritatively by the district court, id. at 310-11, and we need not restitch that fabric in any great detail. It suffices to say that, when the plaintiffs were discharged by Splendorform, a collective bargaining agreement was in force and the ILGWU was the exclusive bargaining representative for the cashiered clique. In the chronology which ensued, the four dates which follow — none disputed — have decretory significance:

1. October 22, 1984 — Splendorform drops the workers.

2. March 21, 1985 — plaintiffs, through counsel, file a charge with the Puerto Rico Labor Relations Board (PRLRB) alleging that Splendorform "violated . . . the current collective bargaining agreement . . . when it laid off forty-seven (47) employees . . . in violation of the seniority clause."

3. June 3, 1985 — plaintiffs, through counsel, file an "informative motion" with the PRLRB amending the charge (a) to increase the body count to eighty-six ( see supra n. 1), (b) to pad the complaint previously levied against the company, and (c) to add the ILGWU as a respondent on the basis that, despite "pretensions" to the contrary, the union "did not fulfill its duty of fair and adequate representation" in respect to the plight of the sewing machine operators.

4. July 23, 1986 — plaintiffs file the instant action in the United States District Court for the District of Puerto Rico.

Though of lesser importance overall, we remark that from July 1985 until early 1986 arbitration proceedings were conducted between the union and the employer. Eventually, a settlement was reached. See Arriaga, 656 F. Supp. at 311. We note, too, that the PRLRB dismissed all of plaintiffs' charges on October 16, 1985. A month later, the Puerto Rico Board denied a petition for reconsideration. At about the same time, plaintiffs filed charges against the ILGWU before the National Labor Relations Board (NLRB). That petition was summarily dismissed on November 29, 1985.

II. DISCUSSION

Summary judgment is, of course, proper so long as "the pleadings, depositions, answers to interrogatories, and admissions on file, together with the affidavits, if any, show that there is no genuine issue as to any material fact and that the moving party is entitled to a judgment as a matter of law." Fed.R.Civ.P. 56(c). Given the sheer chronicity of the four critical events listed above — the timing of which was conclusively buttoned down — we think that brevis disposition was altogether appropriate in this instance. Plaintiffs' union suit was too late a bloomer.

In DelCostello v. International Brotherhood of Teamsters, 462 U.S. at 169-72, 103 S.Ct. at 2293-95, the Court held that an adscititious six month statute of limitations, derived from § 10(b) of the LMRA, applied to hybrid § 301/fair representations actions such as the one at bar. The limitations clock is activated by knowledge, actual or constructive; it begins to tick when the challenged conduct comes to light. "A cause of action in a hybrid Section 301/fair representation suit arises when the plaintiff knows, or reasonably should know, of the acts constituting the union's alleged wrongdoing." Graham v. Bay State Gas Co., 779 F.2d 93, 94 (1st Cir. 1985). Accord Clift v. International Union, United Automobile, Aerospace Agricultural Implement Workers of America (UAW), 818 F.2d 623, 629 (7th Cir. 1987) (per curiam); Metz v. Tootsie Roll Industries, Inc., 715 F.2d 299, 304 (7th Cir. 1983), cert. denied, 464 U.S. 1070, 104 S.Ct. 976, 79 L.Ed.2d 214 (1984); Santos v. District Council, Etc., United Brotherhood of Carpenters and Joiners, 619 F.2d 963, 968-69 (2d Cir. 1980).

In this case, the plaintiffs' own filings place them snugly within the tightest of corsets. They plainly knew of the ILGWU's purported wrongdoing no later than June 3, 1985 — for on that date they filed an elaborate "informative motion" with the PRLRB, citing style and size as to the ill-fitting ways of the union. They claimed then to have lifted the petticoat of "pretensions" and to have glimpsed the perfidy which underlay it. Having spied the wrongdoing, the aggrieved workers were bound to act upon this knowledge in a timely fashion, that is, to sue within the six month limitations period or forever hold their peace. By neglecting to file a complaint for well over a year thereafter, they are undone.

The appellants argue that the pendency of the charges which they instituted before the PRLRB and the NLRB, respectively, served to impede the march of time. The Court, however, has made it crystal clear that an employee whose interests have been slighted by his union can simultaneously tread both administrative and judicial paths. Vaca v. Sipes, 386 U.S. 171, 185-86, 87 S.Ct. 903, 914-15, 17 L.Ed.2d 842 (1967). Accordingly, it would make precious little sense, given the policy considerations which undergird DelCostello, to put so commonplace a stumbling block in the way of the six month statutory period. The Court, after all, has historically been reluctant to invoke tolling in circumstances where a claimant rides parallel horses in search of relief. See International Union of Electrical, Radio and Machine Workers, Local 790 v. Robbins Myers, Inc., 429 U.S. 229, 236-40, 97 S.Ct. 441, 446-49, 50 L.Ed.2d 427 (1976) (collectively-bargained grievance procedures as juxtaposed with Title VII); Johnson v. Railway Express Agency, Inc., 421 U.S. 454, 460-62, 95 S.Ct. 1716, 1720-21, 44 L.Ed.2d 295 (1975) (Title VII administrative procedures juxtaposed with 42 U.S.C. § 1981); cf. De Arroyo v. Sindicato de Trabajadores Packinghouse, AFL-CIO, 425 F.2d 281, 287 (1st Cir.) (describing jurisdiction of NLRB and district courts vis-a-vis § 301 claims as "concurrent"), cert. denied, 400 U.S. 877, 91 S.Ct. 117, 27 L.Ed.2d 114 (1970).

The proof of the pudding is in the caselaw. It has consentiently been held that a filing with the NLRB does not prevent the statute of limitations from accruing on a fair representation claim. E.g., Kolomick v. United Steelworkers of America, District 8, AFL-CIO, 762 F.2d 354, 355-57 (4th Cir. 1985); Aarsvold v. Greyhound Lines, Inc., 724 F.2d 72, 73 (8th Cir. 1983) (per curiam), cert. denied, 467 U.S. 1253, 104 S.Ct. 3538, 82 L.Ed.2d 842 (1984). Although we had previously declined to speak on this precise question, see McNutt v. Airco Industrial Gases Division, 687 F.2d 539, 543 (1st Cir. 1982), we do so today. We rule that the filing of an unfair labor practice charge with the NLRB does not toll the statute of limitations on a hybrid § 301/fair representation action arising out of the same nucleus of operative fact.

The PRLRB proceedings stand on no higher ground. As with the NLRB, the federal courts and the Puerto Rico Board share certain areas of concurrent jurisdiction. See Volkswagen de Puerto Rico, Inc. v. PRLRB, 454 F.2d 38, 45 (1st Cir. 1972). Though they may be directed to many of the same uplifting ends, however, the proceedings and remedies available before the Puerto Rico Board and in the federal district courts remain separate, distinct, and independent. Parties cannot be permitted to play one forum off against the other, jockeying for tactical advantage. The district court could see no reason why, for tolling purposes, PRLRB filings should be treated any differently from NLRB filings. Arriaga, 656 F. Supp. at 311. Nor do we. The pendency of proceedings before the Puerto Rico Board did not stop or slow the limitations clock in this hybrid § 301/fair representation case. Accord Estades v. Harry M. Stevens, Inc., 593 F. Supp. 778, 782-83 (D.P.R. 1984).

By much the same token, the arbitration proceedings in which the union and the company became enmeshed during the latter half of 1985 and early 1986 had no genuine bearing on the timeliness of plaintiffs' suit. Assuming arguendo that the arbitration which occurred was contractually required by the collective bargaining pact and involved the same general topic as the suit — matters which are far from clear — the plaintiffs were not obliged to exhaust either the grievance protocol or any internal union appeals procedures before prosecuting their hybrid § 301/fair representation action in the courts. See DelCostello, 462 U.S. at 164, 103 S.Ct. at 2290; Clayton v. International Union, United Automobile, Aerospace, Agricultural Implement Workers, 451 U.S. 679, 685, 101 S.Ct. 2088, 2093, 68 L.Ed.2d 538 (1981). In any event, appellants believed they had no fair access to the grievance system (because of the ILGWU's perceived unwillingness to help them) and the agreements in force at the time appellants were discharged did not command exhaustion of internal union procedures.

In a situation like this — where appellants contend that the union, rather than taking up the cudgels on their behalf, played pantywaist — it would be a mockery to force the plaintiffs to go through an arbitration process with the ILGWU as their champion. Cf. Hines v. Anchor Motor Freight, Inc., 424 U.S. 554, 567, 96 S.Ct. 1048, 1058, 47 L.Ed.2d 231 (1976) (union's dereliction of fair representation duty "relieves the employee of an express or implied requirement that disputes be settled through contractual grievance procedures"). It mocks reality no less to argue that these disgruntled workers had the right to pin the tail of the arbitration proceedings onto their hybrid case in order to extend the applicable limitations period. The mere possibility of some mutually-acceptable nonjudicial enforcement was far too insubstantial to excuse the delay.

We need not consider whether, or to what extent, the doctrine of equitable tolling can be harmonized with the message of DelCostello. The long and the short of it is that these plaintiffs have offered no hint of any special circumstances which might invoke such a saving principle. They believed from the first that their lay-offs were impermissible; they realized soon thereafter that the union was oblivious to their interests; they were represented by top-drawer counsel early on; they garnered enough information by the following spring to file exegetic accounts with the PRLRB detailing the perceived shortcomings of both the company and the ILGWU. The challenged conduct had occurred and had been laid bare to plaintiffs' view by June 3, 1985 at the outside. See supra n. 2. Under these circumstances, the failure to sue within six months after June of 1985 was inexcusable. The law required considerably more bustle than was displayed.

III. CONCLUSION

We need go no further. There is no genuine issue as to any material fact. The district court was plainly right in granting summary judgment in favor of the appellees. Whatever slips may have been made in the course of the company reorganization, none was made in the court below.

Affirmed.