What are these little creatures living inside a silk web?
From the comments above (in particular, "it's head and mouthpart vaguely resemble that of the termite") it is possible that what is here is a Webspinner colony (Order Embioptera); if so you either have one of the few species in which the male is wingless, or the colony was without adults of that sex when your question was asked.  Webspinners are distantly related to termites, but have little or no economic importance (some species have been accidentally spread by man).  The Wikipedia article (https://en.wikipedia.org/wiki/Embioptera) has some basic information on the group (including photographs of both sexes and of nymphs), and references for further information; identification of species from Bangladesh will be problematic, as Edward S. Ross (the expert on this group from the mid-1940s, and not fully replaced--he has retired) had reportedly collected enough undescribed species to more than double the known diversity.