PACKAKD.] EEPEODUCTIVE HABITS OF BKANCHIPODID^. 425 



and described by Dr. E. Buclibolz, in bis "Brancbipus Grubii Ton Dy- 

 bowsky," Tafel III, fig. 6, witb tbe exception tbat tbe blind append-" 

 age of tbe descending testis is missing. 



Tbe smallest Larval stage I obtained from tbe Glendale pond measured 

 3mm jjj lengtb, but wben mounted in glycerine jelly I could not tell 

 wbetber it was a Cbirocepbalus or an Eubrancbipus larva, as tbe fi'ontal 

 tentacles were not exposed. Tbe 

 same tbing occurred in three otber 

 larger larvaj. One larva of 4:J""^ in 

 lengtb sbowed tbe appendage as illus- 

 trated by Fig. 48. Tbe inner basal 

 clasper-book just budded, is turned 

 do^vnward, tbe anterior, upjjer sur- 

 face of the second anteunse and tbe 

 frontal tentacle is seen. Another 

 larva scarcely larger, second antennae pio. 49._c. iioimani, second antenna with 

 in about tbe same stage of develop- ^011*^1 tentacle, liom above. 

 ment, exhibits tbe frontal tentacle as illustrated by fig. 49. It appears, 

 and I judge from twenty-six mounted beads (in glycerine jelly) tbat tbe 

 growth of tbe frontal tentacles of our Ghirocephalus is very rapid, its en- 

 tire lengtb being i:)robably attained between two exuviations. 



II. — LAIiVAL STAGES OF APUS LUCASANUS Packard ESTHERIA COM- 



PLEXiMANUs Pack. AND Streptogephalus texanus Packard 

 (Plates XXXIV, XXXV). 



Prom dry mud received from Dr. L. Watson, of Ellis, Kans., I batcbed 

 numerous specimens of larvai of both Streptocephalus texanus Pack, and 

 Ustheria eomijleximanus Pack, but only tbree specimens of Apus lucas- 

 anus Pack. Tbe mixture of mud and fresb water was kept at a tempe- 

 rature of about 75° to 80° F. during tbe summer montbs, and in nearly 

 every instance, after tbe third or fourtb day, I could, witb the naked 

 eye, observe some small larvse actively swimming about in tbe aqua- 

 rium. The larvae of 8treptoce])halus, as well as tbose of J/, com-pleximanus^ 

 look at first like little wbite birds, and Prevost, in Jurine's "Histoire 

 des Mouocles," in 1820, bas compared tbe larvae of Chiroceplialus in a 

 similar manner. 



I have often obtained from one and tbe same lump of mud botb tbe 

 very small Xauplii of Estlieria compleximanus and tbe Streptocephalus 

 texanus but, strange as it apx)ears, wben tbe larvae of tbe two genera 

 were thus together, only those of tbe former (Estberia) survived, but 

 those of tbe latter rapidly died off. In tbe single instance, w^ben three 

 Apus larvae of several millimeters lengtb were found at tbel30ttom,tbey 

 were also tbe only occuj)ants of tbe jar. F. Spangenberg bas drawn at- 

 tention to tbis fact on page 61 of bis paper on BrancMpus stagnalis. He 

 says tbat a single larva of Apus cancriformis kills in a few days a 

 number of Brancbij)us larvae. How one kills tbe otber I could not ob- 

 serve, but have either raised Streptocepbalus alone or Estberia or 

 Apus alone. It is very likely tbat tbe secretion of tbe antennal gland, 

 whicb is present in all members of tbis family, whose outlet is under tbe 

 base of tbe second antennae, is antagonistic to otber sjDecies. Tbe prin- 

 cipal function of tbe gland is believed to be for lubrication, to assist tbe 

 constantly-moving second antennae. Its early api^earance in tbe larva, 

 its comi)aratively large development, togetber witb its distinct orifice, 

 may give support to my opinion. 



F. Brauer, C. Claus, and F. Spangenberg agree tbat tbe new-born 

 Apus sinks to the bottom, and gradually, witb sluggisb motions, rises 



