latory organ, it must operate during the nocturnal flights that 

 these bugs frequently take, as it seemed impossible that it could 

 operate under water. This organ also occurs only in the males, 

 and not in all the species." 



The remarks were illustrated by two microscope slides and by 

 figures of the only Hawaiian Corixid, Arctocorisa blackburni (F. 

 B. White) which has so far only been found in these Islands, al- 

 though it belongs to a Central American and Antillean group 

 characterized by the shape of the anterior tibiae in the males. 



Mr. O. H. SwEZEY then read his "Observations on Insects Dur- 

 ing a Recent Trip on Hazcaii/' illustrated by numerous specimens: 



HYMENOPTERA 



Sceliphron caementarimn: No adults were seen, but the nests of 

 this mud-dauber wasp were common, and they always con- 

 tained larvae or pupae, which shows that this species is con- 

 tinuing the habit of hibernation which it had in the States, 

 where it hibernates as larvae in the cells of its mud-nest. 



Odynerus nigripennis: Very abundant. They gather the larvae 

 of Hymenia recurvalis and other green caterpillars to store 

 up for food for their young. Many other species of Odynerus 

 are abundant. 



Polistes anrifer and another species are everywhere in cane fields, 

 feeding upon the "honey dew" deposited upon the cane leaves 

 by the leaf-hoppers. 



Xylocopa brasilianorum: This large carpenter bee is abundant 

 and does considerable damage to fence and telephone posts 

 and some buildings, especially such as are made of redwood 

 lumber. 



Ants: Swarms of them in cane fields, and they must consume a 

 great many of the young leaf-hoppers. 



EcthrodelpJvax fairchildii: This leaf-hopper parasite was seen 

 only in the plantations of Kau, one plantation of Kohala, 

 and at Puako. Numerous attempts have been made to intro- 

 duce it in the plantations of the Hilo and Hamakua Districts, 

 but it apparently has failed to become established. 



Chalets obsenrata, 



Pimpla hazvaiiensis, 



Echthromorpha maculipennis, and 



