LIFE HISTORY AND HABITS OF TWO NEW NEMATODES 

 PARASITIC ON INSECTS^ 



[PRELIMINARY PAPER] 



By J. H. Merrill, Assistant Entomologist in Charge of Fruit-Insect Control, and A. 

 L. Ford, Assistant in Life-History Studies, Kansas State Agricultural Experiment 

 Station 



INTRODUCTION 



While investigating the life history and methods of control of the elm 

 borer (Saperda iridentata Oliv.) and the termite {Leucotermes Itccifugus 

 Rossi) at the Kansas Agricultural Experiment Station, two new nematodes 

 were found, one parasitic on the former and the other parasitic on the 

 latter. One hundred and twenty-one adult beetles obtained from one tree ^ 

 were placed in breeding cages, but in no instance were eggs deposited, 

 and both sexes eventually weakened and died. Examination after death 

 showed that the intestines were so filled with nematodes that in only one 

 female were eggs even developed in the body. The death rate due to 

 nematode parasitization was apparently loo per cent. Several colonies 

 of Leucotermes Itccifugus were placed in salve boxes, together with food. 

 Inasmuch as Saperda iridentata had shown so high a nematode para- 

 sitization, it was naturally suggested that nematodes might be present 

 in the termites. Accordingly a number of these insects were killed and 

 examined, with the result that nematodes were found infesting the head 

 in varying degrees. Of the colonies taken, 76.92 per cent were para- 

 sitized with nematodes. The parasitism of the individuals in single 

 colonies ranged from o to 100 per cent. 



DIPLOGASTER LABIATA 



The nematodes were submitted to Dr. N. A. Cobb, of the Bureau of 

 Plant Industry, United States Department of Agriculture, for identifi- 

 cation. He found that the nematode parasitizing Saperda iridentata 

 was a new species which he named "Diplogasier labiata" (fig. i ; 2, 

 A-H), and described as follows: 



12 17 21 '59'^' 9' 

 Diplogaster labiata, n. sp. 2" , — 4^2 — 4I2 — 474 — 279 ^'^^ ™™" ^'^^^ formula was de- 

 rived from a single specimen.) The thin layers of the transparent, colorless, naked 

 cuticle are traversed by fine transverse striae, resolvable with high powers into rows of 

 dots, more particularly near the head and on the tail, those on the tail being some- 

 what irregularly placed. The cuticle is also longitudinally striated, and the dots of the 

 transverse striations are coincident with those of the longitudinal striatic ns. The longi- 



• Contribution from the Entomological Laboratory, Kansas State Agricultural College, No. 17. This 

 paper embodies the results of some of the investigations undertaken by the authors in the prosecution of 

 projects Kos. 13 and loi, Kansas Agricultural Experiment Station. 



2 A tent was placed around an elm tree so that all emerging insects might be secured for breeding purposes. 



Journal of Agricultural Research, Vol. VI, No. 3 



Dept. of Agriculture, Washington, D. C. Apr. 17, 1916 



dd Kans. — 2 



(115) 



