OF WASHINGTON. 71 



about his grounds at Sunbury, with large perforations and 

 apparently killed by birds, and probably by the house wren. 

 In one instance a species of Attus was observed feeding on the 

 remnants of one of these gutted insects, and he suggested that 

 the beetles observed by Dr. Marx may, in part at least, have 

 been killed by birds. 



Dr. Fox thought that the birds would snap off the wings 

 and head of the insects mentioned and swallow the balance 

 entire, and believed that the holes had probably been eaten 

 out by spiders. 



Prof. Riley described his recent investigations of the life- 

 history and habits of Sp/iecius speciosus, exhibiting specimens 

 of the egg in situ on Cicadas, and of the young and full-grown 

 larvae and cocoons. 



Careful drawings were also shown illustrating the different 

 stages and habits of the insect. 



He stated that Sphecius was always rather common in the 

 District, but this year was particularly abundant in the De 

 partment grounds from the last week of July into August. 

 Advantage was taken of this to endeavor to work out the full 

 life-history of this insect. This had been traced from the egg 

 to the cocoon. The transformation to the pupal state would 

 not take place till later, probably not much in advance of the 

 appearance of the adults next year. An interesting point men 

 tioned was the rapidity of the development of the larva. This 

 had not been fully followed, but the larval period was judged 

 not to exceed a week. It was stated also that Sphecius 

 undoubtedly requires dry ground in which to undergo the 

 transformations. Excessive moisture induces mould in the 

 Cicadas, and many specimens unearthed were destroyed by 

 this agent ; and Cicadas in burrows in dryer earth were found 

 one year old, and apparently perfect. 



Prof. Riley described the habit of the Sphecius larva in con 

 structing its cocoon, which is silken, with enough earth incor 

 porated to make a dense pod. 



The egg was described, and also the frequently many- 

 branched burrows excavated by the adult insect. 



