OBSERVATIONS ON THE SPINED SOLDIER BUG. 



159 



12, but, their number being reduced by insufficient food supply and by 

 cannibalism, 7 only reached maturity. The first of these to become 

 adult molted its fifth nymphal skin on September 23, and the last 

 one of the seven to become adult molted its last nymphal skin on Sep- 

 tember 27, making a range of from 36 to 40 days for the nymphal 

 stages and from 44 to 48 days for all immature stages, including the 

 ^gg. The average duration of the immature stages of the seven speci- 

 mens was approximately 46 days, with an average daily mean tempera- 

 ture of 61.5° F. The approximate total positive temperatures (above 

 32° F.) during the developmental period in this case was 1,357° F. ; 

 to which, if we add the approximate total positive temperature 

 required by the female after reaching maturity, before any eggs are 

 deposited, we get 1,708° F. for the approximate total positive tem- 

 perature of the life cycle in the instances here recorded. The total 

 positive temperatures at Amherst, Mass., from the 1st of May to the 

 15th of October, inclusive, would make a maximum of 3 annual gen- 

 erations possible at this rate, considering that earlier than the month 

 of May and later than the 15th of October the development is prac- 

 tically nil. Of the two specimens under observation, the adult life 

 of the female extended from July 16 to September 6 and that of the 

 male from July 17 to August 29. The total number of days in the 

 case of the female being 53 and the male 44, the average of the pair 

 was 48^ days. Death took place very slowly in each case and was 

 apparently due to natural causes. 



OBSERVATIONS ON THE FEEDING HABITS. 



Desiring to obtain a definite idea of the value of this species as an 

 enemy of the elm leaf -beetle, the two specimens, from the time they 

 were taken on July 9, were fed exclusively on the larvae of this beetle 

 as long as it was possible to obtain them in sufficient numbers. 

 Before molting the fourth nymphal skin the two bugs ate four full- 

 grown elm leaf-beetle larvae. Their food during the six days of 

 their fifth nymphal or " pupal " stage and during their entire adult 

 life is shown in the following tables : 



Feeding record of two bugs in fifth nymphal instar. 

 Food: Elm leaf-beetle larvae (Galerucella luteola Miill. ). 



Date, July, 1902. 



Full grown. 



Three-fourths 

 grown. 



One-half 

 grown. 



One-fourth 

 grown. 



All 



stages, 

 total 

 de- 

 stroyed. 



Eaten. 



Partly 

 eaten. 



Eaten. 



Partly 

 eaten. 



Eaten. 



Partly 



eaten. 



Eaten. 



Partly 



eaten. 



11 



2 

 2 

 9 

















2 



12 



13-16 



..... 

 2 



3 



1 



..... 



2 

 1 



..... 



2 





9 

 15 











Total, Gdays 



4 



1 



3 



1 



2 





26 



