Life-histovTj of Dasylielea obscura, Winnertz. 589 



Keilin, D. (1917). " Recherches sur le3 Anthomyides a larves carni- 

 vores." Parasitology, vol. ix. pp. .325-4o0, pis. v.-xy. 



(1920). "On a new Saccharomycete, Monosporella tmicuspidafa, 



gen. n. nom., n. sp., parasitic in the Body-cavity of a Dipterous 

 I.arva {Dasyhelea ohscuru, AVinnertz)." Parasitology, vol. xii. 

 pp. 8:3-91. 



(1920). "On Two new Gregarines, AUantocystis dnsyhelei, n.g., 



u. sp., and Dendror/iyncJnts system', n g., n. sp., parasitic in the 

 Alimentary Canal of tlie Dipterous Larvae, JJasyhelea ohscura, 

 Winn., and Systenus sp." Parasitology, vol. xii. pp. 15-4-lo8, 

 pi. X. 



(1921). " On the Life-history'of Helicosporidhim parasiticum, n. g., 



n. sp., a new Type of Protist parasitic in the Larva of Dasyhelea 

 ohscura, Winnertz (Diptera Ceratopogonidfe), and in some other 

 Arthropods." Parasitology, vol. xiii. pp. 97-113, pis. iv.-vi. 



Iaboulbb:ne, A. (1869). " Histoire des m(^tamorphoses du Cerato- 

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MiK, J. (1888). " Zur Biologie von Ceratopogon, Meig., nehst Berschrei- 

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E]ETH, J. Th. (1915). " Die Metamorphose der Culicoidinen (rerato- 

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 pp. 377-4i2. 



X. EXPLANATION OF THE PLATES. 



[All the figures concern Dasyhelea ohscura, Winnertz.] 



Plate XIX. 

 Fig. 1. Head of a full-grown larva, seen from the side: an., antennae; 



cl,, clypeus ; h., hypopharynx ; /., labium ; M., maxillaj ; 



m., mandibles ; s., duct of salivary glands ; 1-14, fourteen 



pairs of sensory orj^aus. 

 Fig. 2. Labrum, seen from the ventral side. 

 Fig. 3. Maxilla, seen from the side. 

 Fig. 4. Egg taken out of the uterus of the $ , showing the gelatinous 



layer with small chitinous rods surrounding it. 

 Fig. 5. Antenna of the larva. 

 Fig. 6, Ilypopharynx, seen ventrally : /., lateral wing-like processes ; 



v., posterior ridge of the ventral plate ; rd., lateral bifurcated 



rods connecting the hypopharynx with the labium ; 



s., salivary duct ; v., ventral plate. 

 Fig. 7. Hypopharynx, seen laterally : cL, dorsal plate; o., cesophagus; 



other letters as in fig. 6. 

 Fig. 8. Larva, full-grown, seen laterally, 



Plate XX. 



Fig. 9. Abdominal segments of the larva, showing the characteristic 



pigmented pattern. 

 Fig. 10. Labrum, seen dorsally. 

 Fig. 11. Posterior end of the larva, seen laterally, showing the hooks, h., 



and the lateral protuberance, ;j. 

 Fig. 12. Posterior end of the larva, seen dorsally, showing 2 pairs of 



hooks. 

 Fig. 13. Posterior end of the larva, seen ventrally, showing 4 pairs of 



hooks. 



