PSOCIDAE 



397 



panied by rapping the front of the head on the paper, but Mr. 

 Derham could not be sure that the sound 

 was produced in that manner, because each 

 stroke was also accompanied by a peculiar 

 shudder, or recoil. After a prolonged tick- 

 ing he observed that another individual of 

 the other sex made its appearance. The 

 species figured by Mr. Derham more 

 resembles a Hyperetes than it does either '^' 



of our two known book-lice, AtvO^O^ and Fio. 248.-The Wr death- 

 Clothilla. watch of Upminster. 



IsTumerous species of Psocidae are pre- iita rB^ttTii i.""'" 

 served in amber ; Hagen ^ has made a 



careful study, based on a considerable number of specimens, 

 of about thirteen such species. They belong to no less than 

 nine genera and five sub - families. Sphaeropsocus is the most 

 remarkable ; this Insect has a well - developed prothorax, as 



is the case in the wingless 

 I'socids, and a pair of large 

 wings or tegmina meeting 

 by a straight suture along 

 the back, as is usual in 

 beetles, though quite un- 

 known in existing Psocidae. 

 Another species, Amphiento- 

 mum paradoxum, has the 

 body and appendages covered 

 with scales like a butterfly 

 or moth ; other species, found 

 in gum -copal or still liv- 

 ing, have scales on various 

 parts of the body, but not to so great an extent as this amber 

 species. The genus Amphientomum, is still represented in Ceylon 

 and elsewhere by living forms ; Packard has figured some of the 

 scales ; ^ they appear to be extremely similar to those of Lepi- 

 doptera or Thysanura. The facts connected with this fauna of 

 amber Psocidae would seem to show that the family was formerly 

 more extensive and important than it is at present ; we should 

 therefore expect to find numerous fossil forms in strata of date 



1 Stettin, ent. Zeit. xliii. 1882, p. 265. - P. Boston Soc. xiii. 1871, p- 407. 



Fig. 249. — Sphaeropsocus Jmnowii. From 

 amber. x 30. (After Hagen.) 



