24 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES. 



Anthidium serranum, n. sp. 



Male, length about 151/2 mm. ; similar to male A. illustre, but 

 not so large, and the pnbeseence, even on thoracic dorsum is 

 white ; the .color and markings are practically the same in the 

 two species. The last dorsal segment of the abdomen is yellow, 

 and not so deeply notched as in A. illustre, the incision being 

 about twice as broad as deep, with rather a curved margin, 

 whereas in illustre it is more angular, with straight sides; the 

 median tooth (at the bottom of the incision) is narrow and 

 black, and is -separated by a yellow area from the black longi- 

 tudinal mark at the base of the^egment, whereas in illustre this 

 tooth is very broad (triangular) and broadly united by a black 

 band with the base of the segment. The genitalia are of the 

 same type in both species, the parts in illustre being more ro- 

 bust. A. serranum has a yellow mark on the scape, and the 

 third antenna! segment shows a yellow spot. 



Hab.— Rock Creek, Calif., one specimen taken by Dr. David- 

 son. Named after Father Serra, the founder of the California 

 missions. 



Trypoxylon apicalis Fox—Its Nesting Habits. 



BY DR. A. DAVIDSON 



This wasp is somewhat frequently met with in the neighbor- 

 hood of Los Angeles. The young are bred in the hollow stems 

 of plants,, the parent apparently utilizing any suitable stem 

 of a medium size. The variable diameter of the stems occupied 

 by this wasp, and the frequent discovery of other species of 

 wasps or even bees, in the same cavity has led me to infer that 

 this species does not usually excavate its o^^ti nesting site. The 

 hollow stem adopted is divided into cells by concavo-convex 

 discs of clay, the concavity in every instance facing upwards. 

 These discs are inserted at very irregular intervals, so that the 

 cells vary from half an inch to four inches in length. The co- 

 coons are straw colored, fragile, diaphanous shells one-half 

 inch long, and one-eighth of an inch wide. If, as fre- 

 quently happens, the cocoon when woven is too small to 

 fill the cavity in which it lies it is not as is most fre- 

 quently the case with other wasps simply attached to 

 the sides, but is neatly suspended in the center of the 

 stem cavity, so that on cross section it appears like a 

 wheel with the cocoon as a hub and the irregular suspending 

 threads as spokes. The suspending threads are frequently very 

 few in number, in one instance I found it centrally supported 

 by only four threads. The suspending of the cocoon must in 



