lS94-] ENTOMOLOGICAL NEWS. 221 



being that: " In any case I consider it certain that parthenogenesis is the 

 primitive mode, and that sexual reproduction is subordinate to it." 



The book is one that should be in the hands of every biological student 



for its scientific interest. 



Bisalphide of Carbon as an Insecticide of very limited range has been 

 known for many years, but for ordinary field crops it has not been in gen- 

 eral use. In the 1893 meeting of the Association of Economic Entomolo- 

 gists, Prof. Garman mentioned that he had used it in the garden, covering 

 melon vines with' a tub and allowing a quantity of the bisulphide to evap- 

 orate, destroying thereby the Aphids infesting the vines. This interested 

 me greatly, because the melon louse, Aphis cumuris Forbes, is at times 

 a most destructive pest in parts of New York and New Jersey, and one 

 of the most difficult to deal with, owing to the fact that the leaves are 

 close to the ground and that they curl as soon as seriously effected, making 

 it simply impossible to reach them all, even with an underspray nozzle. 

 A lot of pot-grown plants becoming badly infected with Aphids, in the 

 botanical laboratory, I made a series of experiments which were not re- 

 corded, but which determined that the liquid evaporated slowly; that it 

 killed plant lice very readily, and that it killed plants with equal facility 

 if used in any large quant'ty. The appearance of the lice on canteloupe 

 and citron melons in New Jersey this season gave me an opportunity of 

 making experiments, and Mr. Howard G. Taylor, of Riverton, N. J., 

 kindly permitted me to kill as many hills as might be necessary to carry 

 them on. I procured a dozen wooden bowls, thirteen inches in diameter 

 and six inches deep, inside measurement, and a series of small, graduated 

 tumblers, in which "one teaspoonful" and "one dram" corresponded. 

 To get at the rate of evaporation I poured one dram into a graduate and 

 left it exposed, but placed it in a shaded spot. It required fifteen minutes 

 to disappear completely. Eleven badly'infected hills were then covered 

 by bowls, the vines being crowded under when necessary, and one dram 

 in a graduate was placed under each. At the end of twenty minutes I 

 lifted one bowl, found that less than half the material had evaporated, 

 that all the Coccinellidae were dead, the small lice dying and the Dia- 

 brotica, ants and large viviparous Aphids, were yet all alive. Ten min- 

 utes later there was little change. At the end of three-fourths of an 

 hour, though scarcely more than half the liquid was gone, all save a few 

 of the mature, wingless, viviparous females were dead. In one hour 

 there was yet liquid in all the graduates, but all the Aphids were dead, 

 or appeared so. To test the matter all the hills treated were marked to 

 be examined later. Another series of infested hills were selected, but 

 the experiment was varied by using two drams of bisulphide in some 

 cases, using a shallow saucer in others, pouring the liquid on the ground 

 in two cases and covering other hills with large square boxes, some of 

 them anything but tight. All coverings were left on for one hour, undis- 

 turbed. Examined first a square box covering a shallow saucer with two 

 drams of bisulphide; found this all evaporated and every aphid killed. 



7* 



