INSECT A. 511 



lost ; labial palps transformed into a labella ; hypopharynx setaceous ; larva apodous 

 or with false (i. e. secondary) feet ; mandibulate or metagnathous ; no labial palps ; 

 pupa metagnathous. Diptera (Two-winged Flies). 



14. Wings, none; mandibles long, with serrated edges ; maxilla short, with 4- 

 jointed palp; labial palps 4-jointed, approximated at the base ; labrum distinct; no 

 hypopharynx ; pupa metagnathous ; larva apodous, mandibulate, with obsolete labial 

 palps. Siphonaptera=Aphaniptera (Fleas). 



(.) wings dissimilar, metathorax much larger than mesothorax. 



15. Menognatha, rarely metagnatha ; fore wings coriaceous, rarely lost ; hind 

 wings membranous, folded longitudinally and often transversely, or wanting ; 

 longitudinal veins predominant ; larva mandibulate, Campodeiform or cruciform, 

 with or without legs ; pupa mandibulate. Coleoptera (Beetles). 



* *POL YNEPHRIA . 



1 6. Menognatha and metagnatha ; wings four, similar, membranous, very often 

 areolate, or caducous, or absent ; fore wings the larger ; mesothorax the larger ; 

 pupa mandibulate, with maxillae sometimes transformed ; larva mandibulate, eruci- 

 form, with or without legs. Hymenoptera (Gall-flies, Saw-flies, Ants, Bees, &c.). 



Note. The Strepsiptera are included by Brauer and others among the 

 Coleoptera. Prof. Westwood is still of opinion that they should be retained as a 

 separate order. They are ento-parasitic on various Bees and Wasps. The male is 

 free, has small twisted fore wings, longitudinally folded hind wings, and a large 

 metathorax. It is metagnathous. The mandibles are reduced, the maxillae connate 

 with the labium, their palpi 2-jointed. The female is blind, vermiform, and never 

 quits the host. There is a dorsal canal, by which the male effects impregnation. 

 The ova develope in the coelome ; the Campodeiform larvae escape by the dorsal 

 canal. They are carried by a Bee or Wasp to its nest, where they bore into a grub, 

 and are transformed into apod vermiform larvae. The male pupa is coarctate 

 (p. 153), and perforates one of the abdominal intersegmental membranes of the 

 Bee pupa, protruding only the head, as does also the female. See von Siebold, 

 A. N. ix. (i), 1843; Id. ' Paedogenesis,' Z. W. Z. xx. 1870. 



See lit. pp. 146, 151, 156, 161. 



INSECTA APTERYGOGENEA. See pp. 299-300. Ventral tube and copulation of 

 Collembola, Reuter, Ent. Tidskr. i. 1880, and Zool. Record, 1884, Insecta, p. 277 ; 

 cf. Lemoine, C. R. French Assoc. xi. 1882; development, Lemoine, op. cit. with 

 lit. quoted. 



INSECTA PTERYGOGENEA. 



Ephemeridae, Eaton, Monograph, Tr. L. S. (2), iii. 1884-5; t&rv&e, Vayssiere, 

 A. Sc. N. (6), xiii. 1882 ; development of Chloeon, Lubbock, Tr. L. S. xxiv. 1864, 

 xxv. 1866; vessels to caudal setae, Zimmermann, Z. W. Z. xxxiv. 1880. 



Odonata : mouth-parts, Gerstaecker, ' Morph. Orthoptera Amphibiot.' Festschr. 

 Natf. Freund. Berlin, 1873; larvae, Dufour, A. Sc. N. (3), xvii. 1852 ; of Aeschna 

 grandis, Amans, Rev. des Sc. Nat. Montpellier (3), i. ; tracheae of larva, Hagen 

 Z. A. iii. 1880. 



Plecoptera: Pteronarcys regalis, Newport, Tr. L. S. xx. 1851 ; Gerstaecker, op 

 cit. under Odonata ; Id. ' Vorkommen von Tracheenkieme, &c.' Z. W. Z. xxiv. 



