THE SORGHUM MIDGE. 49 



true hibernating form from which the spring pupae are derived. 

 These enveloped larvae also appear greatly flattened and are ex- 

 tremely thin and delicate in structure. In addition they are them- 

 selves semitransparent, the protoplasmic contents being visibly 

 granular. 



LIFE HISTORY AND HABITS. 



EMERGENCE. 



Emergence of the adults takes place as a rule during the early 

 morning hours during the warmest weather, and later, when the 

 weather turns cool, later in the morning and continuing well into the 

 day. While there is almost a continual emergence in the field from 

 early morning until late in the afternoon, the bulk of emergence occurs 

 as stated, varying with the change of season. 



The pupa, having worked its way from the initial position along- 

 side the ovary to the apex of the spikelet, protrudes about two-thirds 

 of its length . The operation of casting off the pupal skin begins almost 

 immediately. The abdomen is seen to twist with a backward and 

 forward motion, the head and thorax likewise performing the same 

 motions until the pupal skin is gradually split open its entire length, 

 along the dorsum or venter, and sometimes both. The skin does not 

 necessarily part in a well-defined line on either the dorsal or ventral 

 surface, but is often torn raggedly over its entire surface. The head 

 of the adult is gradually thrust through the opening, and then finally 

 the entire body. The legs assist materially in this operation by push- 

 ing back the clinging pupal skin free from the body. When free, 

 the adult is very moist and weak and clmgs to the outer glumes for 

 about ten minutes before it has become sufficiently strong and the 

 wings have dried so as to permit flight. About fifteen minutes elapses 

 from the time the adult begins to free itself from the pupal skin until 

 it is on the w T ing. The cast-off pupal skin remains clinging to the apex 

 of the spikelets. A count of a whole season's emergence, numbering 

 many thousands, fixes the proportion of males to females as three of 

 the latter to one of the former. • 



COPULATION'. 



Immediately after drying, the male takes wing and hovers about 

 the seed head, awaiting the appearance of the females. When the 

 latter have emerged, copulation at once takes place, more often before 

 they have sufficiently dried to fly. When the drying process of the 

 female is complete, she begins to oviposit within the seed glumes, and 

 this operation continues until she has laid her quota of eggs, when 

 death follows. The operations of copulation and oviposit ion are 

 very rapid and are kept up repeatedly until both male and female 

 are dead. 



