Hello, this is Mark. Blaberus identification can only be fully confirmed through genital comparison since many of them can be surprisingly polymorphic with some individuals exhibiting physical characteristics indicative of other closely related species. However, most Blaberus have a few specific visual, odorous and behavioral "tells" that can also be useful identifying markers. The photo is clear enough to see their stouter tegmina in combination with a larger pronotal "spot" suggesting that these are Blaberus fusca aka B. craniifer according to Roth. Also, the broader costal stripes blending with the middle band is also a typical feature of this species especially with females but cannot be used alone to identify B. fusca since it is occasionally exhibited in B. giganteus and quite commonly witnessed on B. atropos as well. Males typically show thinner costal stripes which may or may not touch the middle band. In your case, I would guess that these are B. fusca. Hope this helps.