4 BULLETIN 1016, U. S. DEPARTMENT OF AGRICULTURE. 



and during this time are easily captured. During copulation 

 the female alone remains active, traveling about frequently, and 

 dragging the male helplessly after her. There is little doubt that 

 there are both polyandry and polygamy among the adults of the 

 chinch bug, since they mate an indefinite number of times. 



LIFE HISTORY OF THE CHINCH BUG. 

 OVIPOSITION. 



Under field conditions eggs are placed by the female near or on 

 the plants upon which the insect feeds. Eggs may be found in the 

 soil near the roots, at the base of the plants, but more often occur in 

 the leaf sheath, which appears to be the preferred place. 



In the laboratory bacteriological test tubes, of standard size, stop- 

 pered with absorbent cotton and supplied with parts of corn plants, 

 were found to be the most successful type of egg cage. The corn 

 plants used as hosts were about 6 inches high, with their foliage and 

 the outer roots cut off before introduction into the cage. Sometimes 

 parts of larger cornstalks were used when young corn was not avail- 

 able. In cages where young corn was supplied the eggs were laid 

 on all parts of the plant, but most frequently were placed under the 

 upper epidermal layer of the leaf sheath. This appears to be their 

 favorite location, although many eggs were placed in the cotton 

 stopper of the vial. Where parts of cornstalks were used, the eggs 

 were often found pushed into the pith, on either end, to their entire 

 depth, sometimes two and three together. In the leaf sheaths they 

 are often found in quantities, side by side. In one instance 16 eggs 

 were found placed in this manner in a neat, compact row. With a 

 little care the whole row was lifted out without any of the eggs be- 

 coming detached. It was not often that eggs were placed loosely 

 in the vials. It seems that the female desires to conceal her eggs from 

 possible predacious enemies. 



Eggs in cages were deposited during all hours of the day. It is 

 possible that some may be deposited during the night, but this is 

 doubtful. In the field it is quite likely that very few eggs are de- 

 posited during early morning hours, the temperature at that time of 

 the day being lower and damp, which causes the adults to become 

 numb and therefore sluggish. 



NUMBER OF EGGS DEPOSITED BY A SINGLE INDIVIDUAL. 



Considerable variation has been noted in the number of eggs de- 

 posited by an individual female of this species. Such variation un- 

 doubtedly is governed to some extent by seasonal weather conditions. 

 There is no doubt, however, that some females are by nature more 

 fecund than others. 



