THE CANADIAN ENTOMOLOGIST. 113 



A NEW TYPE OF CORIXID^ (RAMPHOCORIXA BALANODIS, 



N. GEN., ET SP.) WITH AN ACCOUNT OF 



ITS LIFE HISTORY.^ 



BY JAMES FRANCIS ABBOTT, ST. LOUIS, -MO. 



Our knowledge of the developmental history of the water bugs is 

 very incomplete. In the early days of embryology, Corixa was studied 

 by Metschnikoff,- and Brandt,'^ and others with especial reference to the 

 germ layers, the revolution of the embryo, etc. Leon Dufour* had pre. 

 viously. described the eggs of the two European species, Arcioco?'isa 

 striata (L) and heiroglyphica (Duf.). 



The only account of the metamorphosis of any member of the group 

 that I have been able to find is that of F. Buchanan White,'^ who, in 

 addition to describing the egg of Corixa nigrolijieata ( = Arctocerisa 

 fabricii), also described the first moult, remarking that the tarsus of the 

 third pair of legs is but one-jointed. "At this stage," he says, ''they 

 died" — a result which apparently has been obtained by all who have 

 attempted similar observations since. Indeed the rearing of both 

 Notonecta and Corixa seems attended with unusual difficulties,^ although 

 I believe that by the use of mosquito larvae for food, success has been 

 attained with the former. 



The writer has succeeded in carrying a species of Corixid through 

 the whole series of moults from egg to imago, and since the critical study 

 of the larger groups of Hemiptera is greatly hampered by our ignorance 

 of the developmental stages, it seems worth while to describe the various 

 instars in some detail. 



The present species, which appears to be undescribed, has the 

 remarkable habit of attaching its eggs to the carapace of the crayfish, 

 some individuals of which were found almost completely covered by 

 hundreds of tiny eggs. As the writer intends later to discuss this habit in 

 detail, it will be merely alluded to here. The egg-bearing crayfish were 

 captured in a small clear-water pond near Columbia, Mo., the early part 

 of July and were isolated in small aquaria. All the eggs were in the same 

 advanced stage of development, with the red eye spots showing through 

 the shell, and they began to hatch July 8th (1910). 



1. From the Zoological Laboratory of Washing-ton University. 



2. Zeit. wiss. Zool., XVI, 1866, 422-436, Taf., 26 and 27a. 



3. Mem. Acad. Imp. Sci. St. Petersb., XIII, 1869. 



4. Recherches sur les Hémiptères, 1833. 



5. ''Notes on Corixa," Ent. Mon. Mag., X, 1873, 60 63. 



6. Cf. Bueno, Can. Entom., XXXVTI, 390, 1905. 



April, 1912 



