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305 



yet rather obscure ia his mind, he requested me to examine my mater 

 ial, which I have thus been led to do. I have made a figure of this 

 larva which will sufficiently indicate its nature. 



The general form of the trophi, and particularly the anal cerci, fully 

 settle the disputed point, and remove this insect completely from the 

 Mallophaga (none of which possess them), and confirm its position in 

 the Clavicorn series of the Coleoptera. Yet in the larva, as in the 

 imago, the effects of its parasitic life are shown in certain modifications, 

 which approach the running section of the Mallophaga. Without going 

 into details I may say that, besides its general and more decided coleop- 

 terological features, this larva is distinguished by the shortness and 

 stoutness of its legs, by the size and stoutness of the antennae, by the 

 stiff and long depressed hairs on the dorsal and more particularly on 

 the ventral surface, and by the dorsal position of the abdominal spir- 

 acles, all characters approaching the Mallophaga. The first pair of 

 spiracles is lateral, and may be said to be mesothoracic, being placed 

 on the mesothoracic joint, but on a distinct fold. The eight abdominal 

 spiracles are placed on the sid6s of the dorsum, and in this respect re- 

 call the parasitic triuugulin of the Meloid larv?e. The mandibles are 

 barely corneous, and they are more elongate and curved in the younger 

 than in the older larva, while the legs are also relatively stouter, more 

 curved, and with a much longer and sharper claw in the younger larva, 

 which seems well fitted for grasping the hairs of its host. 



There can no longer be any doubt, therefore, about the true position 

 of Platypsyllus. The eggs will probably be found attached in some 

 way to the hairs of the animal they are laid on, much as they are in 

 Mallophaga, and the pupa is probably formed in the nests of the host 

 and not upon the skin, which will explain the reason for its not occur- 

 ring with the larva and imago upon the beaver, either in the case of my 

 specimens or those of Dr. Horn. 



The greatest resemblance of Platypsyllus in the imago state to the 

 Mallophaga is found in the spinous comb on the hind border of the 

 occiput, the arrangement of the spines on the abdomen, and the super- 

 ficial antennal structure, but particularly in the broad trilobed mentum. 

 All of the other characteristics are readily referable to the Coleoptera, 

 though, as Le Conte pointed out, they are composite, recalling in the 

 antenuiie, the Gyrinidte, in the pronotum the Silphidie, in the mesoster- 

 num Limulodes, in the elytra the Staphylindse, in the legs the Anisoto- 

 midte, and in the mandibles the Corylophidre. The scutellum and the 

 five-jointed tarsi at once remove it from Mallophaga, and it is a wonder 

 thatLe Conte and Horn have not more fully insisted on this fact. The 

 trophi are very complicated, and there are various details of structure 

 not noticed or not mentioned by any of the writers upon the subject 

 hitherto. 



I have been led to very carefully examine the imago, and the more 

 closely I have done so, the more completely I realize the accuracy of 



