1913.] Ql 



" Entomologist," from examples captured by Mr. J. Collins outside 

 sand-martin's nests. Here the process lias not advanced very far. 

 The wings are reduced and their venation simplified, more so in the 

 female than in the male, so that her power of flight must be very 

 poor ; and probably after impregnation she creeps back into the 

 martin's burrow. Again, a male Limoaina has recently been found 

 in an ant's nest with wings so short as to be practically function- 

 less. The larva3 of this genus are scavenger sj, and live in and on 

 any kind of refuse or decaying organic matter. Elacliyptera hreri- 

 pennis is another Dipteron in which the wings are greatly reduced 

 in both sexes and c[uite unfitted for iiight. Its life history is not 

 known, but I have only met with it by sweeping the dense beds of 

 Carex paludosa. These beds never change from year to year, and 

 many of them inust be able to boast of an antiquity reaching back 

 into a dim past. In conditions like these the stay-at-home instinct 

 has full scope for acting, and has been, I would suggest, the primary 

 cause in producing the degeneration of the wings in the male and 

 female alike. 



But to return to the apterous Greometer. The starting point in 

 her case I believe to be this stay-at-home instinct and an utter 

 indisposition to use her wings under any circumstances. Nor would 

 this be in any way prejudicial to the welfai'e of her family. These 

 insects are all of them tree-feeders. And trees live to a great age, so 

 that one of them would afford a home almost as permanent as the ants' 

 nest is for the Pliorid, and at the same time provide a supply of food 

 as abundant and as ready to hand as that supplied to the Dipteron 

 Probably in those early days before the wings had begun to degenerate, 

 and the difficulties of finding shelter were great, the species were rare 

 instead of being as at present the bane of the horticulturist. In the 

 same way I would attribute the loss of wings in the Psychids and other 

 Lejndoptera to a great and natural indisposition to fly, which in their 

 case as in the G-eometers would not be counterbalanced but rather en- 

 hanced by the food conditions. 



My argument then is, that the wingless condition, wherever it 

 shows itself, is owing to an overpowering dislike on the part of the 

 insect to use its wings, no matter what may be the provocation. 



Tarrington, Ledbury : 



February 1st, 1913. 



