MEXICAN CONCHUELA IN WESTERN TEXAS IX 1905. 9 



Last of July, after which the Dumber diminishes rapidly. The bugs 



arc strong fliers, which account- for their sudden appearance on a 



given crop, and in some cases for their sudden disappearance from it. 



On July 20-22 no eggs or young could be found on the infested 



peach tree-, nor could any of these stages be found on August 11 and 

 12 after the adults had entirely disappeared from the trees. If any 

 eggs were deposited by the hugs when the latter were attacking the 

 peaches the resulting nymphs were probably carried to the ground 



with the falling- of the fruit, for the interval between the examina- 

 tions was not sufficiently long for them to have reached the winged 

 or adult stage. The only breeding places of consequence found at 

 Barstow were in the alfalfa fields. Here eggs and nymphs were found 

 in large number- on August 11 and 12. A month later the insects 

 had been reduced by at least one-half, and their scarcity was noticeable 

 everywhere except in small areas in some Held- of alfalfa and along 

 the borders near fence- and ditches where the cuttings had not been 

 made at regular intervals. Of $-2 adult pentatomids collected in the 

 alfalfa fields September 12, 26 were P. ligata and 6 P. sayi. At the 

 next examination, on October 13, it was evident that the insects were 

 -till decreasing in number.-, but the nymphs in the la-t two stages 

 were proportionally more abundant than before. In the lot of 16 

 adults and 41) nymphs collected at that time. P. sayi was not repre- 

 sented. The last examination, made on November 14. showed that 

 the conchuelas had almost entirely disappeared: a half hour's search 

 where, at the time of previous examination-, they had been found 

 most abundant, resulted in the capture of only 6 adults, no nymph- 

 being seen. 



NATURAL ENEMIES. 



EGG PARASITES. 



Minute v<^ parasites belonging to the family Proctotrypidae are 

 generally known among entomologists to play an important role in 

 checking the multiplication of many insect-, so that anything which 

 affects the number- of these parasites frequently results in a corre- 

 sponding benefit or injury to the crop- attacked by the host insects. 

 If these parasites of the eggs of pentatomids were eliminated, many 

 of the pentatomids would undoubtedly be ranked among our most 

 important insect pests. The importance o\' these parasites in check- 

 ing the multiplication of the conchuela at Barstow in 1905 can be 

 best emphasized by summarizing the results obtained by rearing 

 parasites from eggs collected at that place. 



