PARACLETUS, 65 



Winged forms unknown.* 



Reaumur, more than one hundred years ago, found 

 Aphides in ants' nests ; but Von Heyden was the first 

 to assign genera for these insects. Paraoletus, Forda, 

 and Trama comprise some minute species which, so far 

 as observation yet goes, are apterous and subterranean 

 in habit. Burmeister subsequently added BMzobius, 

 which expresses an underground habit ; and Passerini 

 has found it convenient to class these several genera 

 together under the section Bhizohiince, an arrangement 

 which for the present may be considered good. Some 

 name must be found for tribes or sections, and it is 

 difl&cult to avoid meanings too distinctive in such 

 names — distinctions which further research might 

 render it necessary to qualify. 



Root-feeding Aphides are now known to obtain in 

 many dissimilar genera, such as Siphonopliora, Aphis, 

 Schizoneura, Pemphigus, and Phylloxera. It would, 

 therefore, seem to be desirable that all comprehensive 

 tribes should have some trivial name which shall not 

 be too exclusive on the one hand, or unmeaning on 

 the other. 



It has long been a problem to solve what habit and 

 condition are assumed by those Aphides which appear 

 to be restricted to short-lived annual plants for their 

 sustenance. When such plants die and become rotten, 

 what becomes of the insects during the eight months 

 when no food seems fitted for their use ? Three 

 hypotheses may be advanced to meet this difficulty. 



1st. Immediate descent into the soil, attended by 

 subterranean oviposition. 



2nd. Migration of the imperfect females to plants of 

 other species, followed by complete development of the 

 cycle upon that plant. 



3rd. Dimorphism, amounting, perhaps, in some cases, 

 to the passage into more complex forms, hitherto regar- 

 ded as stable species in the ordinary sense of the term. 



* Walker's description, if sucli, appears to me too vague to allow of 

 identification. Vide ' Cat. Homop.,' vol. iv, p. 1062. 



