260 [November, 



and the middle acctabula and coxap, and, in the apterous forms, the 

 shape of the metaphragma, offer good specific characters in many 

 Gerridce, although they have not hitherto been used as such by the 

 students of this group. 



In some apterous Gerridce there is a remarkable dimorphism in 

 the structure of the mesonotum. In the same species it is possible 

 to find two apterous forms, both with well-developed genitalia : one 

 with the pronotum more or less fused with the mesonotum and pro- 

 longed backwards in a broadly rounded process, reaching the metano- 

 tum, but with the apical margin free, at a somewhat higher level than 

 the metanotum, quite as in the winged form ; the other with the 

 mesonotum distinctly separated from the pronotum, and the posterior 

 process truncated at the apex, with the postero-lateral margins slightly 

 sinuate, the whole margin of the process closely embracing the 

 adjoining margin of the metanotum. I believe this last form, although 

 capable of copulating, has not undergone its final ecdysis. Without 

 knowledge of this dimorphism, one might easily be induced to describe 

 the two forms as distinct species. 



Tammerfors, Finland : 



September 26th, 1902. 



THREE NEW GENERA OF COCCIDM FROM CEYLON. 



BY E. ERNEST GREEN, P.E.S., Government Entomologist. 



I have been requested to establish the following genera to permit 

 of their inclusion in the " Genera Insectorum " now in course of 

 publication. The species will be described more fully, in their proper 

 place, in the " Coccidce of Ceylon." 



A.NOMALOCOCCUS, gen. nov. 

 Fam. AsTEROLECANiora:. 



Allied to Lecaniodiaspis ; but female forming no sac or test. 



Adult <j? naked. Anal ring with more than eight hairs. Other characters as 

 in Lecaniodiaspis. Antennae present ; legs wanting. Anal orifice surrounded by 

 chitinous plates. Perforate discs on dorsum. 



Male puparium similar to that of Lecaniodiaspis, with hinged operculum 

 behind. 



The single species, at present known, occurs only in nests of an arboreal ant. 

 It is probable that this habitat has led to (he suppression of the test usual in the 

 family. 



Type : A, cremastogastri. 



