236 Transactions. — Zoology. 



Subdivision IDIOCOCCIDJE, Subcl. Nov. 



Last year I had to report two genera as to which I was 

 then unable to decide their proper position. One of these, 

 Sphcerococcus, included only one species ; the other, Cylindro- 

 coccus, had two, and possibly three. Since then I have 

 received specimens of three species which I propose to place 

 in Spluzrococcus, and I have been able to fix definitely 

 the affinities of the third species of Cylindrococcus. Under 

 these circumstances not only can I maintain the genera 

 established last year, but I find it advisable to erect a new 

 subdivision to include both of them, for it is not possible to 

 attach them to any hitherto known. As for their group 

 affinities, I shall leave them amongst the Coccidince, because 

 they certainly are more nearly related to the members of that 

 group than to the Lecanids ; but, even so, their characters are 

 so strange that I have thought it best to indicate the fact by 

 the name of rny new subdivision. Moreover, having decided 

 thus much, I propose to characterize the Idiococcida by such 

 wide and comprehensive features as will permit the future 

 inclusion therein of other genera which may hereafter be 

 discovered : in fact, I mean the subdivision to serve as a 

 receptacle for, perhaps, many insects which cannot possibly 

 enter into the others, and so we may avoid, as far as possible, 

 multiplication of names. 



Idiococcid^. 



Adult females active or stationary ; gall-making, or naked, 

 or producing cotton or wax. Anal tubercles entirely absent ; 

 anal ring hairless. Antennae with usually less than seven 

 joints. Body not prolonged posteriorly. 



The insects belonging to this subdivision are separated 

 from the Monophlebida by the absence of anal tubercles and. 

 by the antennae ; from the Brachyscclida by the absence of 

 any abdominal prolongation or "tail"; from the Acantlm- 

 coccidce and the Dactylopidce. by the absence of anal tubercles, 

 and the hairless anogenital ring. They come nearest, per- 

 haps, to the subdivision Coccidcz, which includes only the 

 single genus Coccus (cochineal), and in which the anogenital 

 ring is also hairless. But Coccus cacti possesses (though very 

 small and inconspicuous) the usual anal tubercles. More- 

 over, although I do not lay much stress upon external simi- 

 larity or dissimilarity, I cannot bring myself to consider 

 Coccus as really closely allied to either Sphcerococcus or 

 Cylindrococcus. This question has given me an amount of 

 trouble and study which anybody except a systematic ento- 

 mologist would probably consider excessive ; and it is only 

 after several months of hesitation and frequent changes of 



