LIST OF ILLUSTRATIONS. XIII 



Page, 

 abdominal segment; ISp, first abdominal spiracle; IT, propodeum (first 

 abdominal tergum); k, scuto-scutellar suture of mesonotum; iVi, pronotum; 

 iVg, metanotum; PI3, pis, upper and lower subdivisions of the metapleurum; 

 PNs, metapostnotum fused with IT; Ps^, mesopleural suture; Psc2, meso- 

 prescutum; r, lateral suture of mesepisternum ; S2, mesosternum; SCI2, prin- 

 cipal part of mesoscutellum; SCI2, anterior subdivision of mesoscutellum; 

 SCI2, mesoscutum; Tg, tegula; Wp2, WP3, pleural wing processes; z, dorsal 



suture of mesepisternum 81 



Axillary sclerites; A, of front wing of Treviex columba; B, of hind wing of Tremex 

 columba; C, of front wing of Apis mellifera; D, of hind wing of Apis mellifera; 

 lAx, first axillary; 2 Ax, second axillary; SAx, third axillary; Sax, accessory 

 sclerite of third axillary; 4ax, fourth axillary; AxD, disk of coxo-axillary 

 muscle attached to second axillary; y, muscle-bearing sclerite attached to 



fourth axillary of front wing in Apis mellifera 84 



Coxopodias tristani 94 



Coxopodias tristani. Second antenna 94 



Coxopodias tristani. First three segments of thorax (imderside) 94 



Coxopodias tristani. First maxilla, a, inner lobe; b, outer lobe 94 



Anilocra acuta. X 2 138 



Head of dog tapeworm 140 



Head of lynx tapeworm 140 



Small hooks of dog tapeworm 141 



Large and small hooks of lynx tapeworm 141 



Mature proglottid 142 



Gravid proglottid showing unusual uterine branching 142 



Gravid proglottid 142 



Margin of proglottids with developing eggs in utero 143 



Sagittal section showing cross section of transverse canal between adjacent 

 proglottids. c, cirrus; c. p., cirrus pouch; I. e. c, longitudinal excretory 

 canal; I. m., longitudinal muscles; n., nerve; t. e. c, transverse excretory 



canal; t. m., transverse muscles ; ut., uterus; v., valve; va., vagina 145 



Alaba supralirata 154 



Nucleus of Alaba supralirata 154 



Alaba jeannettx 155 



Nucleus of Alaba jeannettx 155 



Anarrhichas lupus 158 



Anarrhichas lupus, shoulder girdle 159 



Lycichthys paucidens, shoulder girdle 160 



Anarrhichihys ocellatus, shoulder girdle 160 



Lycichthys scale 1"^ 



Bknnius pholis, shoulder girdle 161 



Bhnnius ocellaris, shoulder girdle 162 



Lycichthys fortidens -'67 



Lycichthys paucidens, upper teeth 167 



Lycichthys paucidens, mandibular teeth 167 



Anarrhichas lupus, upper teeth 170 



Anarrhichas lupus, mandibular teeth 171 



Anarrhichas lepturus 171 



Table showing comparative time spent in the egg as free swimmers and as para- 

 sites by the developing larvae of typical genera from each of the five groups 



mentioned 1"^*^ 



Perissocentrus chilensis, female. Hind femm- and tibia, inner side 236 



Calorileya cearx, female 2"^' 



