June, '10] DICKERSOX : RHYXCHITES BICOLOR, FABR. 317 



apparently pushing- the egg down into the bottom of the cavity and 

 covering the opening. In this operation the value of the ball and 

 socket like connection of the head with the thorax was evidenced, for 

 without changing its position the insect was able to move its head 

 around from side to side. Whether the covering of the puncture is a 

 secretion of the plant caused by the injury or in part is some secre- 

 tion of the weevil is not quite evident. At any rate it forms a dis- 

 tinct covering, light in color at first and gradually darkening. 



An examination of the seed capsule shows that the punctures extend 

 through the outer covering and sometimes into the bases of the seeds, 

 resting within it and measure 2 mm. in depth. The egg is oval in 

 outline, measuring .9 mm. in length by .65-.70 mm. in width, and is 

 light in color with a yellowish tinge given it by the contents. It rests 

 in the bottom of the puncture with the longest diameter parallel with 

 the direction of the cavity. 



Punctures were found in the seed capsules of the blossoms as well 

 as those from which the petals had fallen and as many as 8 were noted 

 in a single one. On several instances two punctures were observed 

 so close together that they extended into each other at their bases 

 and in all such cases only a single egg was found, so that it appeared 

 as if the first egg had been destroyed by the weevil, in the operation 

 of making the second puncture. 



Hatching of the eggs began the first of July and by the middle of 

 the month most of them had hatched. No unhatched eggs were found 

 on July 22 when a number of punctured seed capsules were examined, 

 although a verj^ few young larvae were found as late as early Septem- 

 ber. The larvffi became weU developed by August and soon after 

 the middle of that month many full grown ones were found. By early 

 September most of the larvie had left the seed capsules, which in many 

 cases had become hard and diT- 



THE EFFECTS OF FUMIGATION WITH HYDROCYANIC 

 GAS ON THE HUMAN SYSTEM 



By W. W. YoTHERs, Bureau of Entomology. U. S. Department of Ac;riculture 



Owing to the extremely poisonous nature of hydrocyanic gas, the 

 literature on this subject contains many cautions in regard to its use. 

 While I believe these are on the whole justifiable, they make the 

 uninitiated unduly afraid of the dangers. I doubt if there has ever 

 been a single death from fumigating — at least from fumigating orange 

 trees. The experience of the workers on the White Fly Investigations 

 of the Bureau of Entomology in Florida shows that only rarely 



