POLYMORPHA — PTINIDAE 



247 



present imperfect state of knowledge ^ it is not necessary to treat 

 them separatel3^ Ptinidae are sometimes very destructive to dried 

 animal matter, and attack specimens in 

 museums ; Anobiides bore into wood, and 

 apparently emerge as perfect Insects only 

 for a very brief period; Atwlium ()Sito- 

 drejxi) paniceum is, however, by no means 

 restricted in its tastes ; it must possess 

 extraordinary powers of digestion, as we 

 have known it to pass several consecu- 

 tive generations on a diet of opium ; it 

 has also been reported to thrive on 

 tablets of dried compressed meat ; in 

 India it is said to disintegrate books ; a 

 more usual food of the Insect is, how- 

 ever, hard biscuits ; weevilly biscuits are 

 known to every sailor, and the so-called " weevil " is usually 

 the larva of A. paniceum (Fig. 127, B). In the case of this Insect 

 we have not detected more than one spiracle (situate on the 

 first thoracic segment) ; the other known larvae of Anobiides are 

 said to possess eight abdominal spiracles. The skeleton in some 



Fig. 126. — "Biscuit-weevil.' 

 Anobium paniceum. 



Fig. 127. — Earlj' 

 stages of Anobium 

 j)aniceum. A, Eggs, 

 variable in form ; 

 E, larva ; C, pupa ; 

 D, asymmetrical 

 processes terminat- 

 ing body of pupa. 

 [This larva is pro- 

 bably the " book- 

 worm " of librar- 

 ians]. 



of this sub-family is extremely modified, so as to allow the 

 Insects to pack themselves up in repose ; the head is folded in 

 over the chest, and a cavity existing on the breast is thus closed 

 by the head ; in this cavity the antennae and the prominent 

 mouth-parts are received and protected ; the legs shut together 



^ It is probable that we do not know more than the fiftieth part of the existing 

 species, most of which lead lives that render them very difficult to find. 



