( clxxxi ) 



than in the $) ; and sometimes they actually mepA there, form- 

 ing (in the frontal view) a complete arch. This occurs in the 

 ^ of Apis (the Hive Bee) and also in those of two Fossorial 

 Genera, viz. Astata and Homogambrus. The 9 syes of all 

 these insects are normal. 



(2) The $ antennae (also, of course, sense-organs) are gener- 

 ally longer than those of the $ $, and have further almost 

 always one more joint (13, as against 12, in Fossors, Wasps, 

 and Bees ; but the numbers vary in various Ants). It is, by 

 the bye, rather curious that neither in the Sawflies, nor the 

 Chrysids, and perhaps in no Hymenopterous groups outside 

 the Aculeates, is a difference in the number of these joints a 

 Sexual character.* 



In several cases, e. g. Scolia (Fossors), Vesj^a (Wasps), 

 Eucera and Ealictus (Bees), the antennae of the $, though 

 not otherwise abnormal, are inordinately long as compared 

 with those of the $, distinguishing the two sexes of most 

 species at a glance. But many $ antennal-characters are 

 thoroughly paradoxical. The last joint is sharply inflexed and 

 becomes a sort of hook in some Wasps (Odynerus spp. of the 

 Groups " Ancistrocervs" and ^' Liooiotiis," also Eimienes, etc); 

 it is sickle-shaped in Sphecius, and some spp. of Bembex and 

 Stizus, also in Didineis (Fossors), and in certain Osmia spp. 

 (Bees). Three or more joints at the apex of the ^ antenna 

 are rolled up into a knot-like entanglement in Dinetus (Fossors), 

 Odyneri of the group ^^ Hoplopus" (Wasps), and Systropha 

 (Bees) ; again the middle joints, or some of them, are strangely 

 excavated, denticulated, produced into spinose processes, tuber- 

 culate, clothed with curious pilosity, or otherwise eccentric, 

 in S $ oi various Genera or Species, these peculiarities being 

 so constant in each species as to be absolutely relied upon by 

 systematists. Such phenomena are prevalent both in Bees 

 and Fossors, but especially in the latter. Again, in many 

 Prosopis $^ (Bees) the "scape" or basal antennal-joint is 

 extravagantly dilated, and often (as though to call attention 

 to it) peculiarly coloured, in front, but not behind ! Lastly, 

 one Pompilid Genus or Subgenus, viz. Glavelia, has the $ 

 antennae " pectinate," a character almost unpai^alleled among 

 * See Note A. at the end of the Address. 



