CHAPTER X 



STORIES ABOUT DIGGING WASPS 



An Ammophila that Accomplished an Astonishing Job in Masonry Work 

 • A Collision with a^Priononyx and the Result 



This summer, while passing considerable 

 time at Diablo, Contra Costa county, I noted 

 the presence in the flower gardens of an un- 

 usual number of species of wasps and bees. 

 It occurred to me that these insects being so 

 common that later on I ought to be able to 

 find their nesting places and thereby have 

 opportunity to observe and study acts of their 

 home life. I knew from my reading on the 

 subject where to look for the nesting places 

 of the species that are least seen in or about 

 human habitations and are almost wholly un- 

 known to the common public, such as the 

 Halictus, Ovinia and Megachile of the bee fam- 

 ily and the Eumonidae, Crabonidae, Cerceris 

 and Ammophila, of what is commonly known 

 as the Wasp family. I was particularly desirous 

 of finding an Ammophila "at home" and ac- 

 quainting myself from personal observation 

 how she constructed her abiding place and 

 provided for her progeny. The members of 

 this genus are easily recognized, being about 

 the most slender, long-legged and short - 

 winged of the tribe. Some of them are an 

 inch and a quarter in length. I found them 

 among the most numerous of the visitants of 

 the flower gardens and the hope of having my 

 curiosfty satisfied was correspondingly raised. 



I had read in the details of the life history 

 of this particular insect as given by two ob- 

 servers that it was the habit of one species of 

 Ammophila to excavate its nest in sand beds, 

 therefore I began my search by inspecting and 

 watching at all the sandy places I could find. 

 After a couple of weeks had passed and I had 

 about . given up expectation of meeting the 

 lady wasp as I had wished, one day in the 

 latter part of July, soon after lunch, while 

 walking over a piece of ground that had been 

 leveled off for a house foundation in a lot 

 adjacent to our place, I discovered an Am- 

 mophila in the act of going into a shallow hole 

 in solid ground. I afterwards learned that 

 this species of the family sought this kind of 

 soil for its nest. 



There was no mistake about the identifica- 

 tion. It was certainly the wasp I was looking 

 for, but was she making a nest? This was 

 hard ground full of little pieces of rock and 

 no sand. I said to myself, if she has no ob- 

 jections I will try to discover what she is 

 doing, if not making a nest, in soil so differ- 

 ent from that credited to her habit. 



The hole at this time was apparently abput 

 an inch and a half deep on an incline of about 

 45 degrees. I stood at a distance of about 15 

 feet away from the place of her operations 

 when I first discovered her. From this posi- 



tion I saw her go into the hole and remain 

 about ten seconds, then emerge backwards, 

 taking the wing as she got out, rising about a 

 foot above the ground, going not more than 

 16 or 18 inches away, then back to the hole. 

 This act was repeated several times, when I 

 concluded she was excavating a place for a 

 nest and the trips out were for the purpose 

 of disposing of the material excavated. While 

 she was in the ground I would move a foot 

 or two at a time hearer to the point of her 

 operations. My presence did not seem to at- 

 tract her attention until I reached a position 

 of about four feet from her hole; then when 

 she came out, instead of going back immedi- 

 ately, she flew out, making a wide circle 

 around the hole, then once or twice around 

 me; then lit on the ground, lying flat. After 

 about 10 seconds she flew to the hole, making 

 a small circle or two over it and then resumed 

 her work, apparently having assured herself 

 that my presence bore no menace. While I 

 felt sure that she was bringing out the exca- 

 vated material in the short trips she was 

 making, I could not see the operation of drop- 

 ping the material, so I concluded to make a 

 nearer approach and finally obtained a sitting 

 position about two and one-half feet from 

 the hole. When she came out and found me 

 so near she appeared quite agitated. She 

 flew around me several times, then made 

 larger circles as if to see if there was" any- 

 thing dangerous connected with this intrusion. 

 She lit on the ground several times, some- 

 times near and other times some distance 

 away, always lying flat, a position I never saw 

 any of the wasp family assume before. (The 

 Peckhams noted this peculiar action by a 

 Priononyx wasp as new to them.) I remained 

 without movement, fearful that I had been 

 too impatient and that my disturbance would 

 cause the insect to cease her work; so I was 

 greatly pleased to see her finally resume labor 

 in the hole. I could now not only see the 

 pieces of dirt and rock, but could hear them 

 drop as she threw them out while on the wine:. 

 I timed her trips — they were seldom less 

 than 10 seconds or longer than 15 seconds. I 

 estimated that she averaged about 12 seconds 

 to each load, which would be at the rate of 

 about 300 in an hour. Judging from the sizes 

 of the pieces I recovered as she threw them 

 out, I concluded she made at least an inch 

 and a half in depth in an hour. Some of the 

 pieces were not larger than a pin-head, while 

 occasionally she would drag out a fragment 

 of rock too heavy to fly off with. These 

 would be left within four or five inches of the 



