78 SANITARY ENTOMOLOGY 



of Geotrupes stercorarius (possibly the larva of Physocephalus sexala- 

 tus), Filaria ephemeridarum in the abdominal cavity of the larvae of 

 Ephemera vulgafa and OUgoneuria rhenana, Filara ri/tipleuritis (of 

 Magalhacs, 1900, not Deslongchamps, 1824) in the abdominal cavity of 

 Periplamta americana (possibly a Gongylonema according to Seurat), 

 Filaria stomoxeos in Stomoxys calcitrans (possibly the larva of Hab- 

 ronema microstoma), Mastophorus echiurus, and Cephalacanthus mona- 

 canthus in Tenehrio vioUtor (probably larvae of Protospirura miiris), 

 Mastophorus glohocandatus and Cephalacanthus triacanthus in 

 Geotrupes stercorarius (possibly larvae of Physocephalus sexalatus). 



4. Mermithidae 



These worms which resemble the nematodes and are usually grouped 

 with them are not known to be of importance in medical zoology. One 

 species, of uncertain identity, is of interest, however, as it is the so-called 

 "cabbage snake" whose presence among the leaves of cabbage has alarmed 

 people who have encountered it. This worm, like others of the same 

 family, undoubtedly passes through a portion of its development in the 

 body of an insect, probably one of the common caterpillars that attack 

 cabbage. Similar worms have been found in apples. 



GORDIACEA OR HORSE-HAIR WORMS 



The Gordiacea or horse-hair worms (as which they are popularly 

 known from the superstitious belief that they are animated horse hairs) 

 are of medical interest because several species have been recorded as 

 parasites of man. They gain entrance to the alimentary tract by being 

 swallowed in drinking water. The adults are of not uncommon occur- 

 rence in springs and other surface waters. When swallowed by human 

 beings they are usually soon vomited up but they have in some cases 

 apparently survived in the intestine for several months before the}^ were 

 finally expelled. In some species, and probably in all, insects serve as 

 hosts for the larval stages. The adults deposit their eggs in the water 

 in which they live. The larvae hatching from the eggs enter the bodies 

 of insects such as grasshoppers (as for example, in the case of Gordius 

 rohustus) or crickets (as for example, in the case of Paragordius varius) 

 or in the case of other species they may enter aquatic insect larvae, 

 which may later be devoured by carnivorous water insects. In the latter 

 the worms undergo their development until they have reached or ap- 

 proached maturity when they burst out of the infested insect and escape 

 into the water. The following species of Gordiacea have been recorded 

 as accidental parasites of man: Gordius aquaticus, G. chilensis. Para- 



