88 ENTOMOLOGICAL NEWS [Mar., '22 



These cannibalistic traits are more in evidence when the gerrids 

 have been deprived of food for two or more weeks. This 

 statement regarding the cannibalism of these two species of 

 water-striders is somewhat at variance with the observations of 

 McCook 2 , who has not seen such food responses of gerrids. 



While most of the observations on water-striders in captivity 

 seem to indicate that they prefer fresh food, yet they have been 

 seen to feed on recently dead insects and also on those that 

 have been dead so long that they are beginning to decay. Both 

 G err is rcmigis and Gcrris marginatits have been observed to 

 use as food freshly killed and stale individuals of their own 

 kind, also Miisca domestica and Drosophila ampelophila in a 

 similar condition. 



These observations seem to indicate that both species of 

 gerrids are indiscriminate feeders and apparently will use as 

 food many kinds of animal bodies. Little choice appears to be 

 shown, so long as it is possible to push their bill-like mouth- 

 parts through the exoskeleton into the softer tissues. 



A Shower of Corixidae (Heter.). 



In 1917 the writer published a Review of instances of "Showers of 

 Organic Matter"* and genuine cases of insect rain were found to be 

 few. This year the writer received, through the kindness of Dr. A. K. 

 Fisher, a mass of Corixidae with the following note by Mrs. A. P. 

 Bigelow, of Ogden, Utah, the collector. 



"I am mailing you a box containing samples of a swarm of insects 

 which fell near here last night. A few were dead and the living were 

 unable to raise themselves from the ground though provided with tiny 

 gauze wings. They fell in a thick swarm covering a space not to exceed 

 six feet and pattered like hail on the straw hat of the farmer as he sat 

 by his door about 9 P. M. They lay thickly covering the ground. I saw 

 them this morning (August 3, 1921) still unable to fly and lying in 

 thick heaps." 



Subsequent inquiry developed the fact that there was no light which 

 might have attracted the insects. This question, among others, asked for 

 safety's sake, was really unnecessary since such small insects rarely if 

 ever, come to light in numbers so great as to form "thick heaps." 



These water boatmen (of the genera Ramphocorixa and Corf.ro) had 

 a generally frayed appearance, and although no unusual wind was noted 

 when they fell it is probable that somewhere on their journey they had 

 encountered some destructive wind phenomenon that resulted in their 

 precipitation to the ground. W. L. McATEE, U. S. Biological Survey, 

 Washington, D. C. 



- 1907. McCook, H. C. Nature's Craftsmen. New York, p. 267. 



* Monthly Weather Review, 45, pp. 217-224, May, 1917. 



