1920] Patch: Aphids and Coccids 165 



The metamorphosis of the male coccid falls in line with 

 that of the female for the first, and in many respects for the 

 second instar. 



Then, as though the somatic memory of Hemipteron inher- 

 itance reclaims its own, the insect reverts to the methods of 

 the order to which it belongs and develops antennae, legs and 

 wings by the external gradual process proper to the Rhychota. 

 In the confusion, however, between the generalized Hemipteron 

 transformation by gradual external development of adult 

 characters, and the specialized tendency of the parasitic coccid 

 toward atrophy of these same characters, the male, attempting 

 both, accomplishes neither in typical shape; but strikes a 

 happy medium all his own by passing through his latter 

 nymphal instars beakless and quiescent, and emerging a queer 

 atom of an insect in possession of remarkable eyes, well devel- 

 oped legs and antennae, and usually functional wings (albeit 

 there is little left of the hind pair but the costal hooks), but 

 lacking curiously enough the only emblem of Homopteron 

 relationship which his wingless, eyeless,* legless,* antennaless*, 

 mate can boast — the beak*. 



The biological urge for overproduction is chiefly provided 

 for, among the coccids, by the great number of eggs deposited 

 rather than by a conspicuous shortening of the life term of the 

 generation. Coccid eggs are typically fertilized though there 

 are many instances of parthenogenetic eggs recorded. Partheno- 

 genesis in the coccids, however, does not seem to function 

 toward a greater number of generations per season as w4th the 

 aphids but is merely an alternative of certain species. This is 

 also the case with the ovo-viviparous reproduction of those 

 species where the egg undergoes complete development and 

 hatches within the body of the living female; a process which 

 does not carry the significance of the viviparous reproduction 

 of aphids. 



Except for those species for which apterous and alate males 

 both occur, polymorphism is not exhibited by the coccids, nor 

 do they have an alternation of generations — one being like 

 another in form and habit. Perhaps nowhere else among the 

 insects, however, do we find a more excessive difference in the 

 two sexes than in the extraordinary dimorphism of the coccids. 



*This, of course, can not be said of the whole family. The female, Xylococcus 

 betulcB, for instance, possesses eyes, legs and antenna; and lacks the beak! 



