1914 



ENTOMOLOGICAL SOCIETY. 



77 



genesis, an adaptation of inestimable value to species living under such conditions 

 and dependent upon weakly organized adults for their establishment in favorable 

 conditions. These midges produce only a few eggs and evidently possess very 

 limited powers of flight. The larvae are capable of penetrating only the weaker, 

 semi-rotten tissues of bark and sapwood, and are preyed upon by voracious maggots 



Fig. 3. — Gall Midge Structures. 



belonging to the genera Medeterus, Lonchea and Lestodiplosis. All too frequently 

 the only evidence of Miastor infestation is the abundance of predaceous maggots 

 which have devoured practically every inhabitant of a once populous colony. The 

 ability to produce young in an indefinite series of generations by maggots advancing 

 in unoccupied tissue is a great advantage in avoiding such enemies as those men- 



