INTRODUCTION 9 



latter part of the nymphal life and by some to the fact that the 

 wings are developed from imaginal discs. The great variation in 

 the length of the quiescent period and the development of the 

 wings of all insects with an incomplete metamorphosis from 

 imaginal discs would show that the hypothesis that the male coccid 

 has a complete metamorphosis is without foundation. This is 

 further accentuated by the fact that the wings of the male coccid 

 are always developed externally, never internally, as in all insects 

 with an incomplete metamorphosis. 



The adult male is identical in form with the hemipterous type 

 except that the bristle-like mandibles and maxillae are wanting 

 and the rostrum is represented by a slight conical projection. The 

 mouth-parts are often incorrectly stated to be wanting. - The state- 

 ment that the ventral pair of ocellanae are developed from and 

 replace the mouth-parts is groundless. The transverse constrictions 

 between the segments of the body, the coriae, are of the usual 

 insectean type and always more distinct than in the first nymphal 

 stage. 



The females are generally stated to have an incomplete meta- 

 morphosis. This has probably arisen through the absence of wings 

 which are the most important external structures that can be used 

 in determining what type of metamorphosis exists. It is safe to 

 conclude, however, since the male has an incomplete metamorphosis 

 and that the members of the other families of this order have a 

 typical incomplete metamorphosis that the females of this family 

 have a similar type. The females of the different genera show a 

 greater diversity in the number of nymphal stages than the males. 

 There may be two, three, or four molts and a corresponding num- 

 ber of nymphal stages. It is an interesting fact that the generalized 

 female coccids have the same number of molts as most of the males 

 and that it approximates the condition found in most insects. 

 There is a direct correlation between the specialization of the 

 structures of the female and the reduction in the number of molts. 

 The most specialized species exist in only three conditions or 

 stages, two of which are nymphal. The first nymphal stage is an 

 active one for migration and location, the second nymphal stage 

 is for feeding and growth, and the third stage or adult stage is for 

 the production of eggs or young. The developing female differs 

 from the male in that she departs farther and farther after each 

 molt from the form and structure of hemipterous and other insects 

 while the males approximate them closer and closer in form. The 

 females become grub;-like or bag-like while the males 'become 

 insect-like. 



