226 LEAF-MINING INSECTS 



Its habits in leaving the leaf and entering the ground are 

 entirely similar to those of the other Fenusinae. 



SCOLIONEURINAE 



Of the ten North American species of the subfamily 

 Scolioneurinae enumerated by MacGillivray one is in the 

 genus Scolioneura, four are in the genus Metallus, three in 

 the genus Parabates and two in the genus Entodecta. So 

 far as known these species are all leaf miners. More notice 

 has been given in literature to miners of the genus Metallus 

 than to members of others of these genera. Careful life- 

 history observations on some of the other species are much 

 to be desired. 



THE BLACK-BERRY LEAF MINER 



Metallus rubi. In the literature of economic entomology 

 there have been four or five accounts of sawfly miners inflicting 

 serious injury upon plantations of blackberries, dewberries or 

 raspberries; and despite some discrepencies between these 

 accounts they are now generally considered to refer to the 

 single species, Metallus rubi. Discrepencies in regard to 

 the time of mining are to be interpreted in the light of cli- 

 matic differences. In Delaware according to Professor 

 Houghton, the first brood emerging in spring begins ovi- 

 positing in late May. The larvae hatching from these eggs 

 were full-fed by the end of June and transformed through 

 pupae into sawflies early in July. The larvae of this 

 second brood are full-fed by late July or early August. 

 In New York and Illinois observations by C. R. Crosby and 

 S. A. Forbes respectively indicate that the second brood of 

 larvae are not full-fed until much later. Professor Crosby 

 observed unhatched eggs of this brood on August 25th and 

 Professor Forbes reports that the larvae had left the leaves 

 and entered the ground by September 25th. At Frederic- 



