December, '17] SCIENTIFIC NOTES 561 



A Suggestion for the Destruction of Cockroaches. The recent successful attempts 

 to destroy bedbugs in dwelling houses by superheating makes the possibihty of killing 

 cockroaches {Blatella germanica) by the same system seem feasible. A number of 

 experiments have been carried out by the writer to ascertain what degrees of heat were 

 fatal to them. It was found that temperatures below 120° F. were variable in their 

 effect, but exposure to a temperature of 122° F. to 140° F. for twenty minutes de- 

 stroyed 100 per cent. IMany difficulties are involved in employing this method, 

 owing to the habit of the cockroach of hiding in cracks, between walls, etc. 



On the other hand cold is also very destructive to the "Croton Bug." We find 

 that exposure to 24° F. for three hours killed 100 per cent, to 18° F. for twenty 

 minutes killed 100 per cent, 10° F. for five minutes killed 100 per cent, to 0° F. for five 

 to ten minutes killed 100 per cent. The appUcation of cold for this purpose would 

 meet with more difficulties than would that of heat. 



The writer has not yet had the opportunity to make a practical test based on these 

 observations, but offers the suggestion for what it may be worth. 



C. W. HowAKD, University Farm, St. Paid, Minnesota. 



27 September, 1917. 



Occurrence of a Fungus-Growing Ant in Louisiana.^ The presence of the fungus- 

 growing ant, Atta texana Buckley, in Louisiana was first brought to the writer's atten- 

 tion on November 8, 1914. This was at Glenmora, Rapides Parish, in the long-leaf 

 pine hills about twenty-five miles south-southeast of Alexandria. Specimens were 

 collected and the identification afterwards verified by Dr. W. M. Wheeler. Farmers 

 in the parish have more recently complained of injury to cultivated crops by the ant. 



The species has hitherto apparently been recorded only from Texas. The follow- 

 ing extract from a letter from a correspondent in Glenmora indicates that they have 

 been present in that section for a long time. The correctness of the tradition which 

 he mentions is, however, as Doctor ^Vheeler has stated in a letter to the writer, 

 rather doubtful because of the improbabihty of queens, without which the species 

 could not become established — being so transported. The correspondent writes as 

 follows: — "There is an old tradition to the effect that the Spaniards brought them 

 to this country from Texas. The old trail leading from San Augustine, via Natchi- 

 toches, to New Orleans passed through this country, and these ants may be found 

 on most of the high sandy land on each side of this trail." 



Thomas H. Jones, Entomological Assistant, 

 Bureau of Entomology, U. S. Dept. of Agriculture. 



Some Sunflower Insects. Weevil Attacks. — Mrs. Cockerell noticed last September 

 that weevil larvae (Desmoris) were able to induce growth in unfertihzed seeds. 

 Bagged sunflower heads which were not fertiUzed produced no seeds, as the plant is 

 not fertile with its own pollen. The ovaries shrink and show no development, but 

 in one such head eleven ovaries contained weevil larvae, and in spite of lack of fertih- 

 zation were large and swollen, larger than the normal seeds. We are reminded of the 

 experiments of Loeb, in which unfertihzed eggs were caused to develop by various 

 stimuh. 



Systena hudsonias Forst, (det. Schwarz) was found eating leaves of Helianthus 

 annuus at Boulder, July 22, 1915. 



Autographa biloba Steph. has been bred from leaves of Helianthus at Montreal 

 (Wirminhtt.). 



1 Approved by the Secretary of Agriculture. 



