.428 MonophlebincB. 



CHAPTER XIII. 

 Sub-family MONOPHLEBIN^. 



This sub-family, although containing the largest members of 

 the whole family, is perhaps less perfectly known than any other. 

 This is chiefly due to the difficulty of obtaining material in 

 sufficient abundance for really accurate study. Many of the 

 genera are represented in most collections by a few individuals 

 too often in a poor state of preservation, and the types have 

 largely been described from superficial characters only. With 

 very few exceptions the species are confined to the tropical and 

 subtropical regions. 



The insects are provided with antennae, limbs, and buccal 

 apparatus in all stages. The limbs are usually robust and 

 •densely chitinous. Dermal pores of a complex structure are a 

 conspicuous feature. There is no setiferous anal ring. Abdominal 

 spiracles are present in all the species. 



Attempts have been made to classify the genera by the number 

 of such spiracles ; but, apart from the fact that their position 

 is usually difficult to locate (owing to the presence of crowded 

 setae or other dermal processes), the species are not yet sufficiently 

 well known to justify such a classification. 



I am unable to find any satisfactory generic distinctions 

 between MonopJilebiis, Drosicha, Llaveia, Tessarabohts, Ortonia^ 

 Guerinia, and MonopJilebulits, and have, accordingly, included them 

 all in the type genus. 



The characters of the two aberrant genera Stigmaccoais and 

 Cryptokermes are not sufficiently well known to enable me to place 

 them with any confidence, and they have been omitted from the 

 following table. It seems possible that both may be more nearly 

 associated with the Margarodincc than with the Motioplilebincs. 

 The basal joint of the antenna of Stigmacoccus is membranous, as 

 in Xylococciis and its allies. Cryptokermes is said to lack mouth- 

 parts in the adult female stage, and to secrete a long tubular 

 anal filament in the nymphal stage. 



