1917 ENTOMOLOGICAL SOCIETY. 19 



»*^fl/u- curdala Mnlil. hi their attacluneiit to the leaves of tlieir ho^U they also vary 

 as the species on >'SalLv peiiolaris is almost equally divided by the blade, while 

 Pontania potnum projects, only very slightly, from the upper side of the leaf. 

 Further, the former species is hollow from the earliest stages, but the latter only 

 becomes so when eaten out by the larvae. A number of the galls from Salix 

 peiiolaris Sm. were collected in 1915, just before the fall of the leaves, and were 

 kept, out-of-doors, in jars- containing earth, during the winter. The adults began 

 to emerge April 15th, and were sent to Mr. S. A. Kohwer, Washington, D.C., who 

 has kindly replied as follows : " 1 have made a preliminary examination of the 

 species and lind that it may easily i)e distinguished from Pontania pomum and 

 that it comes near to P. pisum. 1 think the species is undoubtedly new." 



An interesting observation was made concerning this new species of sawfiy, 

 namely that the aperture of exit is prepared a considerable length of time before 

 the larvfe leave the galls. Just what conditions finally prompt their departure 

 and why their means of escape have to be ready, are points not yet cleared up. 



ISince all sawfiy galls are well advanced in development before the larvae are 

 hatched, it is safe to conclude that the chief stimulus to abnormal growth must 

 emanate from the ovipositor of the insect. The sawflies, when depositing eggs, 

 clasp the opening buds with 'their legs and insert their sawlike ovipositors into the 

 young lea\es from the under side. Into each of the incisions, thus made, an egg 

 is injected. The larvjy, as soon as hatched, commence to feed upon the substance 

 in the interior of the gall, but leave the rind uninjured. 



Since the pear-slug, Eriocampa cerasi Peck makes a similar incision in the 

 leaf, Avithout causing an ^abnormal production of tissue, it is highly probable that 

 in the case of the sawfiy gall-producers, the stimulus is not due to the mechanical 

 efliect of the cutting, but to a chemical action arising from the introduction of 

 some substance by the ovipositor of the insect. 



A specimen of the Compton Tortoise, Vanesm j-ftUnnii, seen April 7th, marked 

 the opening of the entomological season, and throughout the summer butterfiies 

 in general, were plentiful. In this connection the unusual abundance of the Mon- 

 arch, Anosia plexippus L. should be noted. Since 1906, specimens of this species, 

 have not been so numerous in this locality. During August, abundant evidence was 

 furnished at different places of their congregating habits. On the island the 

 l")oplars and willows were favorite resting sites for large flocks. The instinctive 

 tendency to migrate sou't-hward m the autumn must have been the stimulus that 

 impelled them to seek this outlying station. At different times straggling lines 

 of these insects were noted moving Avestward along the lake shore. 



Pontania pctiolariclis Xew Species. Eohwer. 



Belongs to Group 3 of :Marlatt, and is closely allied to saUcis-pisum Walsh, 

 but may be distinguished from that species by the dark l)rown stigma, and by hav- 

 ing the third antennal joint shorter than tlie fourtli. and the third cubital cell 

 much longer than high. 



Toronto, Ontario. Described from a number of females and males reared by 

 A. Cosens from galls on Salir peiiolaris. 



Tupe.— Cat No. roOGi);, U.S.X.M. 



A more extended description of this species will be pulilished in connection 

 with other species of this genu's. 



