THE HORNED SQUASH BUG. 



33 



effect is produced by the prominent angle of the prothorax and the 

 similar markings of the legs. In addition to the increased length of 

 the wing-pads and other observable characters, shown in the illustra- 

 tion, the spines in front of the head which have now made their appear- 

 ance are noticeable. The central portion of the abdominal tubercles are 

 yellow, and yellow alternates with black on the lateral tubercles of the 

 abdomen. The entire body, including the ventral surface, is darker in 

 color. The last antennal joint is black, at least in its posterior moiety, 

 the tip being yellow. Length, about 9 mm . 



LIFE HISTORY. 



The eggs of this species are deposited in much the same manner as 

 are those of the common squash bug, the young making their escape 

 in the same way. Thus far, however, egg masses that have been found 

 are all smaller, numbering not more than about 20, as compared with 

 30 or 40 which are often observed in tristis. 



July 30, in examining watermelons for evidence of insect attack, two 

 masses of eggs of this squash bug were found on different melons, 

 deposited on the under side near the ground. 



Often this species is to be found with its congener, living in different 

 stages in apparent harmony. Colonization is rather less obvious than 

 in the case of tristis. 



A pair of adults was obtained July 14. On the following day they 

 were observed mated and next day 10 eggs were deposited. 



The precise period of the egg from deposition to hatching was not 

 noted. It was presumably about eight days, however. 



The different stages of the nymph of the horned squash bug, with 

 the exception of the first and fifth, occupied five days between each 

 molt, as observed during the hottest weather, represented by an average 

 of about 85° F. 



The first molt occurred two days after hatching; the fifth stage occu- 

 pied six and eight days in different lots. These periods, including the 

 egg, may be tabulated as follows : 



Stage. 



Date. 



Egg Xot observed 



*«-™* K*£SS8:::::: 



Second nymph July 30 to Aug. 4 



(Aug. 3 to 8 



Third nymph < Aug. 4 to 9 



t (Aug. 9 to 16 



^^p" {iSf.iSSM::::: 



(Aug. 15 to 22 



Fifth nymph { Aug. 21 to 28 , 



{ Aug. 3 to 11 



Periods. 



Eight days (estimated). 

 [Two days. 

 Five days. 

 ^Five days. 

 Seven days. 

 [■Five days. 



[Seven days. 

 Eight davs. 



The minimum period of the entire life cycle was thus thirty-two days. 

 In another experiment in which a lot of adults were placed in a large 

 rearing cage together so as to be under more natural conditions than 

 33892— iSo. 19 3 



