THE VICTORIAN NATURALIST. 139 



feel inclined to take up the study of this family of insects Mr. 

 Haskell's book is simply invaluable, everything being written and 

 explained in the same lucid and careful manner which so dis- 

 tinguishes any work this gentleman undertakes. Dr. V. Signoret's 

 great work, " Essai sur les Cochinelles," is one which every student 

 of coccids ought to have in his library, as also the American works 

 of Professors Riley, Comstock, Cognillet, Howard, and others, 

 which teem with valuable scientific and useful information. To 

 enable those who may not have access to the works above alluded 

 to, I have included in this part of my paper some information as 

 regards the characteristics of the family, with a systematic arrange- 

 ment as adopted by Hr. Haskell, feeling assured that such 

 information will be useful to those about to study this large and 

 interesting group of insects. 



The first principal characteristic separating the Coccidas from 

 the rest of the Homoptera, and distinguishable without micros- 

 copic examination, is the absence of wings in the females at all 

 stages of their existence. The second is the absence of any 

 apparatus for feeding and digesting in the males. From these 

 two characteristics it follows that the females can only extend their 

 operations by, at the best, crawling from plant to plant, or by 

 being carried about by birds or other agency ; also, that the males 

 cannot enjoy more than a very short existence. Hence, in any 

 endeavours to destroy these insects, the males may be disregarded 

 and the females only attended to. 



Other distinguishing characteristics, chiefly microscopic, are : — 

 i. The presence of only one joint in the tarsus, or fourth 

 . joint of the leg, in both males and females. 



2. The presence of only two wings, with two halteres, in the 



full-grown males. 



3. The presence of only a single claw terminating the leg in 



both males and females. 



4. The presence of two or more eyes or ocular tubercules, in 



addition to the ordinary pair of eyes, in the full-grown 

 males. 

 In general outward appearance the female insect presents very 

 variable forms. They may be either naked or covered over with 

 some kind of shield, which may be fibrous, waxy, or cottony ; or 

 they may have a thin, powdery meal scattered over them. The 

 covered insects are, of course, stationary, although, in some cases, 

 before reaching their full development, they move about, carrying 

 their houses with them. The naked insects may be either 

 stationary or active. They attach themselves either to the bark 

 or stem of a plant or to the leaves. In the latter case it is rare 

 to see them on the upper side ; but, on turning over a leaf, the 

 under surface is frequently found covered thickly with them. 

 There are, however, many exceptions to the above statement 



