LIST OF ILLUSTRATIONS. 



PLATES. 



Facing page. 



1. Strepsiptera: Families Mengeidse and Myrmecolacidse, males 232 



2. Strepsiptera: Family Stylopidse, males 23? 



3. Strepsiptera: Family Stylopidse, females 232 



4. Strepsiptera: Family Stylopidse, females 232 



5. Strepsiptera: Families Hylechthridae and Xenidse, males 232 



6. Strepsiptera: Family Xenidse, males 232 



7. Strepsiptera: Family Xenidse, males 232 



8. Strepsiptera: Family Xenidse, males 232 



9. Strepsiptera: Family Xenidse, females 232 



10. Strepsiptera: Family Xenidse, males 232 



11. Strepsiptera: Family Xenidse, females 232 



12. Strepsiptera: Family Xenidse, females 232 



13. Strepsiptera: Families Xenidse and Halictophagidse, females 232 



14. Strepsiptera: Families Halictophagidse and Dioxoeeridse, females 232 



15. Strepsiptera: Family Elenchidse, males 232 



TEXT FIGURES. 



Page. 



Fig. 1. — Distorted abdomen of Leionotus annulatus containing Leinotoxenos 



hookeri 31 



Fig. 2. — Diagram comparing nervous system of Strepsiptera with that of other 

 orders. 1. Machilis maritima (Machiloidea), Nervous system gener- 

 alized with a ganglion for each segment; the eighth, ninth, and tenth 

 fused into one mass (from Packard). 2. Termes, species (Isoptera), 

 Ganglia of last five segments fused into one mass (from McMurrich 

 after Gegenbaur). 3. Chironomus plumosus (Diptera), Metathoracic 

 and first abdominal ganglia fused, also ganglia of last four segments 

 fused into one mass (from Packard). 4. Melanoplus spretus (Orthop- 

 tera), Metathoracic and first abdominal ganglia fused; second and 

 third fused; fifth and sixth fused; eighth, ninth, and tenth fused (from 

 Packard). 5. Empis stercorea (Diptera), Prothoracic and mesotho- 

 racic; metathoracic and first abdominal; sixth to tenth abdominal 

 ganglia fused (from Packard). 6. Tabanus bovinus (Diptera), Tho- 

 racic and first abdominal ; seventh to tenth abdominal ganglia fused, 

 and other abdominal ganglia approximate (from Packard). 7. For- 

 mica rufa (Hymenoptera), Meso- and metathoracic and first and sec- 

 ond abdominal; sixth to tenth abdominal ganglia fused (from Brandt). 

 8. JEcilius sulcatus (Coleoptera), Mesothoracic and all following gan- 

 glia fused into one mass (from Brandt). 9. Syrphus ribesii (Diptera), 

 Thoracic and first four abdominal ; sixth to tenth abdominal ganglia 

 fused (from Brandt). 10. Lucanus dama (Coleoptera), Meso- and me- 



XI 



