515 



1 with a slender bristle near end; 2 with two stout bristles near end; 

 5 with a stout bristle about 20 i-i from end, and a short slender one about 

 12 fx from end; 6 and 7 each with a bristle; 8 with several, one, about 

 32 u from apex, being very long, 95 i^i. Anterior leg with femur 4- 

 trochanter 187 ^< long, (diameter of femur about 45), tibia 145, tarsus 

 (excluding claw) about 87; claw 27; claw digitule about 32, with knob 

 about 7 diam. and stem about 2^/^ diam. ; tarsal digitule about 55 long. 



On twigs of wild rose (Rosa), at Coulter, Middle Park, Colorado 

 August 1904. (E. Bethel.) 



The antennae, curiously enough, have almost exactly the measure- 

 ments of the Japanese P. aurantii., Ckll. ^ ; they are also rather like 

 those of P. ehrhorni^ King, but that has the scale about twice as large. 

 P. pruni, Hunter, and P. hunteri, King, are also larger than our insect, 

 especially the latter. The size of the scale, and the form of the ovisac, 

 in P. coidteri are very suggestive of P. ami/gdali, Ckll,, but a com- 

 parison of the type-slide of P. amygdali reveals the following characters 

 in which it diverges strongly from coidteri: (1.) skin quite different, being 

 full of large round and oval hyaline spaces, crowded together. (2.) The 

 second antennal joint is much shorter, 37 to 40 ^< long. (3.) The anterior 

 femur is much broader (4.) The anterior tarsus is shorter, 68 to 70 ,«. 



I will take this opportunity of stating that Mr. Bethel informs me 

 that the types of Pidvinaria innurnerabilis hetlieli, King, were not on 

 Betula, as he at first stated, but on Alnus. 



3. Zur Entwicklungsgeschichte des Sterletts (Acipenser ruthenus). 



I. Embryonalcloake und Bildung des Sinus urogenitalis. 



Von A. Ostroumoff. 



(Mit 2 Figuren.) 



eingeg. 20. September 1905. 



Bei Embryonen mit 21 Somiten (56 Stunden nach der Befruchtung) 

 liegt der cloakale Abschnitt des Darms (Fig. 1 cl) unter der Schwanz- 

 knospe. Er ist im Längsschnitt halbsichelförmig ; einerseits befindet er 

 sich in weiter Kommunikation mit dem Canalis neurentericus [c.n.), ander- 

 seits ist er im Zusammenhang mit dem Reste der Ventrallippe des 

 Urmundes, der in diesem Stadium als Aftergrübchen erscheint, dessen 

 Boden die Aftermembran [A. m. ) darstellt. 



1 It is worth noting that the figures of the marginal spines of P. aurantii and 

 P. psichi given by Mr. Kuwana in Proc. California Acad. Sci., Ser. Ill, Zoology, 

 vol. Ill , PI. X, are apparently transposed ; a fact vphich is likely to mislead those 

 who are not familiar with the original descriptions. I judge from the text (p. 58j 

 that Mr. Kuwana bad the species correctly identified, and that the error on the 

 plate was purely accidental. 



36* 



