34 



MISCELLANEOUS PAPERS. 



of the contained parasite, split off and the parasite began to emerge. In addition to 

 the anterior opening, the pupal rase, in mary instances, split down the back, although 

 this did not hold true with all. In one case the split-off anterior end of the pupal 

 case adliered to the face and antennte of the newly emerged insect and it required 

 fully an hour from the time the parasite was entirely freed from the pupal case until 

 it was freed from that portion which covered its face. 



The longest time in the period of emergence was consumed by the insect in freeing 

 its head and thorax from the pupal case. After this was accomplished the insect 

 rapidly worked the case from its abdomen by the aid of its posterior legs. 



The time of emergence noted varied greatly, depending probably upon the strength 

 of the individual and the hardness of the pupal case. The shortest time noted was 

 4^ minutes from the time the pupal case first began to split until the adult parasite 

 was entirely free. The longest period noted was 1^ hours. These both seemed to 

 be exceptional cases, as five others were timed as follows: (1) 21 minutes, (2) 33 

 minutes, (3) 25 minutes, (4) 28 minutes, and (5) 36 minutes. 



For a short time after freeing itself from the pupal case, the adult 

 parasite remains in one position, busily engaged in cleansing its body. 

 The head and antennae are cleansed by the fore legs and the wings and 



body by the hind legs. These 

 are then cleansed by drawing 

 them through the mandibles. 



WTien the adult first emerges 

 there is a suggestion of pink 

 color in the abdomen. This is 

 explained by the fact that tliis 

 parasite in the larval stage does 

 not expel any excrement, and 

 this accumulation of waste 

 matter is of necessity still con- 

 tained in the abdomen and im- 

 parts to it the crimson color so 

 noticeable in parasitized prepupse. During the change from larva to 

 pu])a this waste product still remains and is, in fact, as before stated, 

 in the abdomen of the arlult upon emergence. In a short time, how- 

 ever, the adult expels this semiliquid, and it forms several minute 

 red spots on the surface beneath. 



/6 /7 /8 /9 20 2/ 22 23 24 25 26 27 28 



Fig. 6.— Diagram illustrating length of pupal stage in 

 14G individuals of Thripoctcnus russcUi. (Original.) 



DESCRIPTION OF NEWLY EMERGED, LIVE ADULT. 



The living adult of Thripoctenus russelli is a very minute insect, 

 being about 0.7 mm. long and 0.2 mm. wide. The head is black, 

 with dark red eyes and light yellow antennae. The thorax is bluish 

 black with the wings hyaline and the legs light yellow, while the 

 abdomen is light yellow with more or less black toward the anal 

 end. The ovipositor is nearly concealed when not in use, but when 

 extended is very long, slender, and light yellow. This insect is shown 

 in figure 7, so that with the technical descrij)tion on page 3.5 a more 

 lengthy description at this time is unnecessary. 



