64 SANITARY ENTOMOLOGY 



of the insects named will hatch, the larvae within twenty days after 

 ingestion of the eggs developing to tlie infective stage. In this stage the 

 larvjE arc coiled up in cysts in the muscles of the prothorax and legs, 

 differing in location from the larvje of G. scutatum which in artificially 

 infected cockroaches, as in their normal hosts, dung beetles, are found 

 encysted in the body cavity. 



Arduenna strongylina (Rudolphi, 1819) Railliet and Henry, 1911 



This nematode in its adult stage occurs in the stomach of the pig. 

 Seurat (1916) has recorded the presence of larval nematodes in the 

 stomach of a pig associated with adults of A. strongylina which he con- 

 siders belong to this species. He has found morphologically similar lai-val 

 nematodes encapsuled in the body cavity of Aphodius rwfus castaneus and 

 states that they also occur in beetles of the genus Onthophagus. Ap- 

 parently no feeding experiments have been carried out. Presumably the 

 life history would be similar to that of Gongylonema scutatum, Proto- 

 spirura muris, etc., that is, the eggs of the parasite passed in the feces are 

 swallowed by beetles, the larvae develop in these insects to the infective 

 stage, and are transferred to the definitive host when the beetles are 

 swallowed by a pig, after which the young worms complete their develop- 

 ment to maturity. Seurat (1919) records the presence of encysted larv;e 

 of A. strongylma in the stomach wall of the Algerian hedgehog (Erinaceus 

 algirus). Apparently, therefore, the larvae of this species that occur 

 encysted in insects, like those of Physocephalus sexalatus and Spirocerca 

 sanguinolenta, if ingested by vertebrates other than the normal hosts of 

 the adult worms, migrate out of the lumen of the digestive tract and 

 become reencysted in the neighboring tissues. 



Physocephalus sexalatus (Molin, 1860) Diesing, 1861 



The adults of this nematode live in the stomach of the pig, dromedary, 

 and donkey. Seurat (1913) has found two successive larval stages pre- 

 ceding the adult in the stomach of the definitive host (donkey) and has 

 also (1916) established the common occurrence of the earlier of these two 

 stages in various dung beetles (Scarahceus YAteuchus^^ sacer, S. 

 [Ateuchetus^^ variolosus, Geotrupes dou£i, Onthophagus nebulosus and 

 O. hedeli). Pigs of course are commonly known to be coprophagus in 

 their feeding habits and Seurat states that the donkeys of Algeria, where 

 his investigations were made, commonly devour fecal matter swarming 

 with dung beetles. The way in which the larvje of P. sexalatus reach their 

 final host is therefore evidently through the ingestion of infested beetles 

 by pigs, donkeys, or dromedaries. Presumably of course the beetles be- 



