198 AMERICAN HYMENOPTERA. 



PLATE XV. 

 Fig. 122. — Bombus {Bombias) rufocinctus , ventral aspect of outer 



spatha. xl7. 

 " 123 — Bombus kirbyellus, ventral aspect of outer spatha. xl7. 

 " 124. — Bombus {Bombias) auricomus, ventral aspect of outer 



spatha. xl7. 

 " 125. — Bombus sitkensis Nylander. Ventral aspect of outer spatha. 



xl7. 

 " 126. — Bombus petmsylvanicus, ventral aspect of outer spatha. 



xl7. 

 " 127. — Bombus separatus, mner spaXha.. xl7. 

 " 128. — Bombus lerricola Kirby. Inner spatha. xl7. 

 " 129. — Boinbus separatus, ventral aspect of outer spatha. xl7. 

 " 130. — Bombus {Bombias) crotchii, inner spatha. xl7. 



PLATE XVI. 

 Fig. 131. — Bombus vagans, ventral aspect of outer spatha. xl7. 

 132. — Bombus pennsylvaniciis, inner spatha. xl7. 

 133. — Bombus impafiens , inner spatha. xl7. 

 134. — Boinbus {Bombias) morrisoni, inner spatha. xl7. 

 135. — Bombus affinis, inner spatha. xl7. 



136. — Bombus {Bombias) auricomus, apex of inner spatha. xl7. 

 137. — Bombus iernarius, ventral aspect of outer spatha. xl7. 

 138. — Bombus appositus, inner and outer spathas together. xl7. 

 139. — Bombus {Bombias) tievadensis, inner spatha. xl7. 

 140. — Bombus perplexus, ventral aspect of outer spatha. xl7. 



PLATE XVII. 



Fig. 141. — Psithyrus ashtoni, inner spatha. x26. 



" 142. — Bombus iernarius, inner spatha. x26. 



" 143. — Bombus separatus, inner spatha. x26. 



" 144. — Bombics sitkensis, inner spatha. x26. 



" 145. — Bombus perplexus, inner spatha. x26. 



" 146. — Psithyrus tricolor, inner spatha. x26. 



PLATE XVIII. 

 Fig. 147. — Bombus dahlbomii Guerin. Genital guide of queen. x68. 

 " 148. — Bombus dolichocephalus YlandWrsch. Outer spatha of male. 



x25. 

 " 149. — Bombus affinis, genital guide of worker. x68. 

 " 150. — Bombus polaris Curtis. Ventral aspect of right side of 



genitalia of male. x80. 

 " 151. — Bombus auricomus, genital guide of queen. x68. 

 " 152. — Bombus rubicundus Smith. Outer spatha of male. x25. 

 " 153. — Bombus funebris Smith. Outer spatha of male. x25. 



