N E W N I A I . T. < ) V 1 1 A (J A 



\r,i 



fr(tin the other siJe. Tlie couunon duct thus formed 

 then goes straight back to the sclerite. The shape of 

 both these organs is very remarkably constant. In one 

 or two genera they present deyiations, and also in a few 

 scattered cases, but these will be described farther on. 



As was pointed out by Kellogg (1896), these organs 

 are not peculiar to the Mallophaga but occur also in 

 the Psocidie, haying been described for these insects 

 by Burgess (1S7S). Outside of these two groups, how- 

 eyer, they are not known to occur. Among the Mallo- 

 phaga they are not of uniyersal occurrence, but are 

 for the most }tart confined to one suborder. Speci- 

 mens of the following genera were had for examination; 

 Ancistrona, Coljtocejjhalum, Docopliorus, Euryruetopus, 

 Giebelia, Goniocotes, Goniodes, Lniiiobothrium, Lipeurus, 

 Menopoa, Xinuus, Sitzi^ehiu, Oncojihorus, PhysudohiUin, 

 Trichodectea, Trinoton. The following table shows the 

 distribution of tiie sclerite and glands among these 

 genera: 



The aboye table shows thai those gtriicru with the 



structures present belong, with the exception of Colpo- 



cephidum, to the suborder Ischnocera; while those in 



which they are absent belong, without exception, to the 



suborder Amblycera. Hence there are no Ischnoceran 



genera in which the sclerite and slands are absent in all 

 n 



