126 Journal of Agricultural Research voi. vi, No. 3 



were observed, none lasted over 4^ minutes. As the mating neared com- 

 pletion, the female became more active and broke free. 



Relation and economy of the sexes- — Both males and females 

 mated repeatedly with different individuals. A single female was ob- 

 served to mate with 7 different males, and during this time laid a total 

 of 317 fertile and 14 infertile eggs. The length of time from the first 

 to the last mating was 13 days. The greatest number of fertile eggs 

 produced from a single mating by any individual under observation was 

 125, but the average number was 52.63. A single male was successfully 

 mated with 10 different females, the latter depositing 624 fertile eggs. 

 The total time which elapsed during these 10 matings was 19 days. 



Time and method of oviposition. — A single instance was observed 

 of a female depositing a fertile egg 30 minutes after mating, although 

 from one to two hours are usually required. The eggs developed in the 

 ovaries in large numbers and were rapidly discharged through the 

 genital pore. With age the females became very sluggish and did not 

 appear to be able to discharge their eggs; consequently these eggs 

 hatched within the body of their parent, where they fed on her internal 

 organs. Usually they were unable to escape, although instances were 

 observed where they escaped through the genital pore of the mother 

 (fig. 2, K). 



Proportion of sexes. — ^Three hundred specimens were examined, 

 and of these 138 were males and 162 were females. In all cultures the 

 females seemed to be more abundant. 



Habits. — These nematodes were found parasitic in the heads of 

 Leiicoiermes lucifugus, where under natural conditions the number varied 

 from o to about 75. Where heavy infestation occurred, the termites 

 became sluggish and often died. These worms were usually more numer- 

 ous in the immediate region of the mouth parts of Leucoiermes lucifugus, 

 although it was not uncommon to find them in the upper part of the cav- 

 ity of the head. A great many termites were dissected, and in no case 

 were nematodes found in the abdomen. In infested colonies nematodes 

 were often seen in the surrounding soil. These usually were found in 

 masses, feeding upon the bodies of dead termites or other available 

 decaying matter. Specimens of D. aerivora placed in water cultures 

 were found to flourish in the same food that was used for D. lahiaia. 

 It was necessary to feed these nematodes each day, for without food 

 they died in a very short time. As in D. lahiata, the presence of food 

 appeared to stimulate copulation and consequently caused an increase in 

 oviposition. 



So far as could be determined, these nematodes showed no preference 

 to either day or night in mating, oviposition, or other habits. 



Length of active breeding stage. — The active breeding life of the 

 female extended over a period of about 13 days, while that of the male 

 was about 19 days. The complete life cycle of D. aerivora required 

 from four to five days. As the individuals of this species which were 



