Report of tee State Entomologist. 



127 



Fig. 52. — The young Gordius 

 TARius, after emerging from the 

 egg, showing different degrees of 

 protrusion of the oral apparatus. 

 (After Leidy.) 



larva, as of a species of fly or other insect, it usually enters the 

 body through the joints of the legs, and becomes encysted, or inclosed 

 in a small sac or bladder, as are the 

 Trichinae. When these larvse are eaten 

 by fish the cyst is broken and the 

 Gordius passes to its second stage. 

 After having remained free in the body 

 for a while, it again becomes encysted 

 in the mucous layer of the intestines. 

 In its third stage it is again free, when 

 it penetrates into the intestines of the 

 fish, whence it passes with the faeces into 

 the water, where it enters upon its final 

 growth, undergoing other changes. Such is its history when enter- 

 ing into aquatic larvae, as elaborated a few years ago by M. A. Villot, 

 a French scientist. Its subsequent changes, when parasitic upon 

 terrestrial insects have not been as fully observed, and just how, at 

 maturity, it succeeds in entering their bodies, is still a mystery. 



Mermis Parasitic on the Apple-worm. 

 The other genus of hairAvorms, Mermis, has occasionally been found 

 within apples, where it occurs as a parasite of the apple-worm, the 

 larva of the codling moth, Garpocapsa pomonella. A notice of Mermis 

 acuminata occurring in some apples in Orange county, N. Y., in 1875, 

 coiled up in the fleshy part of the fruit, about midway between the 

 skin and the core, was given by me in the Thirtieth Annual Report on 

 the N. Y. State Museum of Natural History for the year 1879 (pp. 117-126); 

 also in my Entomological Contributions (No. iv, pp. 5-14). It is therein 

 mentioned that a species of Mermis infests the Garpocapsa pomonella 

 larva, in Europe. According to Dr. Speyer, the Gordiaccea not unfre- 

 quently occur in larvae which feed on tall trees, as well as those which 

 live on plants and shrubs. Wet seasons seem to be productive of the 

 parasitism, and Dr. Speyer recalls a number of years ago, his having 

 met with several of such instances. From an example of Hadena 

 adusta, he had a Merniis emerge of the length of eight and a half 

 inches, and another from Hesperia lineola after it had been pinned. 

 Prof, von Siebold suggests that a heavy dew may so moisten the 

 trunks of trees as to enable the Mermis to ascend them. 



Those who would know more of these interesting creatures, may 

 find an excellent extended article upon them in the First Report 

 of the U. S. Entomological Gommission, 1878, pp. 326-333, from which 

 the illustrations herewith presented have been taken. 



