Mavi 1Q02] 



PSYCHE. 



343 



according to the individual. The testis 

 is a simple capsule ; connected with the 

 base of the jaculatory duct there is a 

 pair of elongate accessory glands or 

 vesiculae seminales. 



The internal anatomy of the Mallo- 

 phaga has been described by Grosse 

 (for the species " Tt-trophthalmiis chil- 

 eiisis" =z Menopo/i titan), by Nusbaum, 

 and latest and in most detail by Snod- 

 grass,* who studied comparatively the 

 various organs in several species. With 

 reference to the alimentary canal, Mal- 

 pighian tubules and reproductive organs 

 (the only organs which have been de- 

 scribed for the Psocidae and can there- 

 fore be compared, with the similar Mall- 

 ophagous organs), Snodgrass finds that 

 the alimentary canal in the Mallophaga 

 presents two types, one being " simple, 

 having no special development at any 

 part" and possessed by the Amblycera, 

 (one of the two sub-orders into which I 

 have divided the Mallophaga) the otiier 

 "complicated by a lateral and backward 

 prolong.rtion of the crop so that the 

 latter forms a large expanded divertic- 

 ulum of the oesophagus." This second 

 type is possessed by all the members of 

 the sub-order Ischnocera. In the simple 

 type the canal corresponds thoroughly 

 well with that of Clothilla, even to the 

 shortness of the intestine as compared 

 with the rectum. With regard to the 

 Malpighian tubules Snodgrass finds their 

 number constant throughout the Mallo- 

 phaga. That number is four, as in 



* Snodgrass, R. E., The Anatomy of the M.illophag.i, in 

 New Mallophaga III, Contrib. to Biol, from tlie Hopkins 

 Seaside Laboratory of Leland Stanford Jr. University, no. 

 XIX, pp. 224, plates 17 plates. 



Clothilla. Finally comparing the repro- 

 ductive organs Snodgrass finds the num- 

 ber of egg tubes to be five in the sub- 

 order Ischnocera and to vary from three 

 to five in the Amblycera. In Clothilla 

 there are five. In the Mallophaga the 

 testes are either two or three in number 

 on a side and there is a pair of seniina- 

 vesicles, with its two members either 

 distinct or more or less fused. In Cloth- 

 illa there is one testis on a side, and a 

 pair of seminal vesicles. 



So far as the comparison can be made 

 then it is obvious that a great similarity 

 in character of internal organs exists in 

 the degraded wingless Psocid Clothilla, 

 and the Mallophaga. 



Finally it is interesting to note the 

 similar habits of Atropos, Clothilla and 

 tiie other dust-lice or book-lice (including 

 all the degenerate wingless Psocids) and 

 the biting bird lice or Mallophaga. 

 These book-lice feed on dry dead organic 

 matter, such as wood and paper, dried 

 insects and dried bird and mammal 

 skins ; the Mallophaga feed exclusively 

 on the dry dead dermal scales, hairs and 

 feathers of mammals and birds. I have 

 found Atropos often in the nests of birds; 

 was it feeding on the feathers there ? 

 What a simple step from the feathers oft 

 the bird to the feathers on the bird ! 

 Then Atropos would be a bird-louse and 

 a new and rather aberrant genus of Mal- 

 lophaga I As a matter of fact in collec- 

 tions of Mallophaga sent in to me, all the 

 specimens presumably collected from the 

 bodies of birds, I have in a few, (very 

 few, truly,) instances received specimens 

 of Atropos. 



