1 86 



Journal of Agricultural Research 



Vol. XV, No. 3 



genitalia being seen in outline through the semitransparent walls (fig. 

 3,A,B). 



With the final molt the wings expand rapidly, and the distinction 

 between males and females and the dimorphic forms of females become 

 clearly marked. 



The adults remain quite constantly on the grass heads and evidently 

 feed for a number of days before mating or egg laying begins. 



The insects cling to the stems or heads of grass quite firmly, the tarsi, 

 which are quite long, being evidently well fitted for securing a firm hold 

 to the parts of the grass. They seem to obtain the best hold on the 

 smaller stems, i>^ to 2 mm. in diameter. On the timothy heads the 

 tarsi catch in the florets, which seems to give them a very firm foothold, 

 as they are not easily dislodged. They could doubtless cling to the 

 heads easily while the hay is being handled. 



On the grass heads they are more commonly found with their heads 

 directed upward, and they show some tendency to mount to the highest 



Fig. 3. — Mirisdolabratus, genital segments: A, Female; B, male of fifth instar nymph; C, female; D, male of 



adult. (Original.) 



point; but they often stand head downward and pass up and down the 

 heads and stems freely. The position with the head upward appears to 

 give them an excellent position for probing into the florets with their 

 beaks. It was noted that in egg laying the females selected small stems 

 of grass, I to i^ mm. in diameter, while in clover stems as much as 

 2)4 mm. diameter were used. Probably the rough or softer stem of 

 clover serves as a good foothold, though the tarsi are too small to clasp 

 around it. 



The insects are not very conspicuous on the grass, even where plentiful, 

 and may be somewhat protected by their form and coloration, especially 

 from a little distance. At close range they are disposed to dodge behind 

 the grass when disturbed, and they can move with considerable celerity. 



The proportion of the sexes and the two forms of female is of interest 

 and possibly of economic significance, since it bears very directly on the 

 ability of the species to spread from the fields in which they hatch. 



In the ordinary field captures the short-winged females were in the 

 majority, and in captures with special effort to obtain all forms they 

 were usually somewhat more numerous than males, a fact that may be 



