392 



NEUROPTERA 



oesophageal bone ; under or within the lingua there is a pair 

 of lingual glands. Judging from Grosse's study of the mouth 

 of Mallophaga, we may conclude that the oesophageal bone will 

 prove to be a sclerite of the hypopharynx. The eyes of the 

 winged forms are frequently remarkably convex, and there are 

 also three ocelli, triangularly placed on the vertex. The head 

 is free and very mobile. The coxae are rather small, exserted, 

 contiguous ; the sterna small. The abdomen has usually ten 

 segments, though sometimes only nine can be detected. 



The thorax in Psocidae usually looks as if it consisted of 

 only two segments. This is due to two opposite conditions : ( 1 ) 

 that in the winged forms the prothorax is reduced to a plate 

 concealed in the fissure between the head and the mesothorax 

 bearing the first pair of wings; (2) that in the wingless forms 

 (Fig. 247), though the prothorax is distinct, the meso- and meta- 

 thorax are fused into one segment. 



The internal anatomy is only very incompletely known. 

 Nitzsch 1 has, however, described the alimentary canal and the 

 reproductive organs of Clothilla pulsatoria. The former is 



FIG. 244. Reproduc- 

 tive organs of Clo- 

 thilla pulsatoria. 

 A, Male ; a, vesi- 

 culae seminales ; b, 

 testes ; c, vasa de- 

 ferentia ; d, ejacu- 

 latory duct. B, 

 Female ; a, b, egg- 

 tubes ; c, oviduct ; 

 d, uterus, contain- 

 ing egg ; e, acces- 

 sory gland (the en- 

 veloping sac in sec- 

 tion) ; /, its duct. 

 (After Nitzsch.) 



remarkably simple : no proventriculus or crop was found ; the 

 stomach is very elongate, and consists of a sac-like anterior 

 portion and an elongate, tubular posterior part. There are four 

 Malpighian tubes. The posterior part of the canal is remark- 

 ably short, the small intestine being scarcely as long as the 

 rectum. The ovaries (Fig. 244, B) consist of five egg-tubes on 

 each side ; connected with the oviduct there is a peculiar acces- 

 sory gland consisting of a sac containing other small sacs each 



1 Germar, Mag. Entomol. iv. 1821, p. 276, pi. ii. 



