SCHIZONEUKA ULMI. 103 



Lichtenstein says that tlie produce of these winged 

 females descend into the ground, and that they hiber- 

 nate at the roots of various grasses. 



If I understand him rightly, he maintains that the 

 cycle of these insects' lives spreads over two years, 

 and the sexes are not seen till the second season. On 

 the other hand. Prof. Eiley says that this habit is not 

 in accordance with his own or M. Derbes observa- 

 tions on Pemphigus cornicularis. 



At present this subterranean habit is so far an open 

 question that it requires more attention than has been 

 bestowed by natiu'alists upon it before it can be said 

 to be scientifically proved. 



In the State of Mississippi Schizoneura Americana 

 sometimes infests the Elm trees so much that Prof. 

 Eiley has seen a matted mass of dead insects under the 

 trees from three to four inches thick. This decaying 

 mass was the food of numerous other insects. 



During someyears the English Aphides are sufficiently 

 plentiful, but occasionally they are difficult to find even 

 in their old haunts. Such was the case in 1879 at 

 Maiden, in Essex, when Mr. E. A. Fitch could only 

 send me a few winged forms collected from rolled elm 

 leaves in the month of October, These were so small 

 that they might almost be taken for another species. 

 It is probable, however, that they were the winged 

 mothers ready to transport the perfect sexes to the 

 places of oviposition. Their expanse of wings was 

 only 0*155 of an inch against the nominal 0"310 of an 

 inch, which last measurement represents an insect born 

 in June. 



I have occasionally plucked leaves of the Elm rolled 

 fro7n helotv iqnvards, but I could not discover any 

 unusual specific distinctions in the insects inhabiting 

 them. 



I quote M. Lichtenstein's words with reference to 

 the migration of these Aphides. " Ce qu'il y a de plus 

 curieux, c'est que la Scliiz. Americana ne quitterait pas 

 I'ormeau et efiPectuerait ses sept changemeuts sur le 



