414 ENTOMOLOGICAL SOCIETY 



ops until it assumes the puparium state, when it is deposited in 

 the form of a short, white, egg-like object without a trace of artic 

 ulation and nearly as large as the abdomen of the parent Next 

 to these are the spider-flies or bat-flies (Nycteribiidae), which pos 

 sess neither wings nor balancers, and are the most degraded and 

 truly parasitic of the Diptera. There are also certain other wing 

 less forms, such as Braula cceca, which infests the Honey-bee. 



Among the Hippoboscids may be particularly mentioned the 

 curious genera Olfersia and Lipoptena, the latter being peculiar in 

 that in the earlier state the flies have wings and live on birds, 

 while later they seek quadrupeds and have no further use for 

 their wings, which are shed. 



In this order (as a unique group or sub-order) I should also 

 include the Pulicidae or fleas, with which all are familiar and 

 which are parasitic on warm-blooded animals, but only in the 

 imago state. Here, therefore, it is the imago which has become 

 modified and fitted for its parasitic habit, and not the larva. The 

 parasitism is, however, incomplete, since some species may live 

 upon different hosts. The fleas differ from the parasitic bugs in 

 this, that, so far as known, the parasitic life or the need of blood 

 from some warm-blooded animal seems to be essential to full de 

 velopment, while the so-called bed-bugs are known to be able to 

 develop without such parasitic life upon animals. 



HEMIPTERA. The only truly parasitic forms in this order 

 belong to the sub-order Pediculina, and are contained in the 

 family Pediculidse or true lice. These are small, wingless, and 

 remarkably modified insects which live upon the skin of mammals 

 and suck their blood. The eggs are fastened to the hairs of the 

 host, and the transformations are incomplete, the young closely 

 resembling the adults. Each species is ordinarily confined to a 

 single host, and the few exceptions in this respect are found upon 

 mammals which are closely allied to the original host. The 

 mouth-parts are capable of great extension and are usually fur 

 nished at the tip with a number of barbs which serve to retain 

 them in position. A large number of species have been described, 

 and three commonly infest the human being. 



We may pass by the Orthoptera, the Dermaptera, the Trichop- 

 tera, and the Mecoptera, as possessing no truly parasitic forms. 

 The same may be said of the Plecoptera, the Odonata, and the 



