MINNESOTA BILL BUGS. 157 



IHipated on the following day. Thev must therefore pass the winter 

 as pupae or adults, or both, within the i)upa cell. Two parasitic 

 cocoons were found, one of which was inside a cell of S. ::cac, 

 judging- from the remains of the larvae in the cell. The other 

 cocoon was apparently in a cell of S. vciiatiis. 



So far as observations go. the native food plant of 6". ::eae is the 

 same as that for 5". 'c'cuatits. The adult beetles will leave the native 

 food for the corn when it is near l)y, and feed upon it with the same 

 relish and the same habits as .b\ 7'ciiatits. Xo eggs of 6". zcac were 

 found in corn. 



The larvae ha\e not been found in corn, but like .S". I'diafiis, 

 spend their lives at the base of and in the central region of the 

 yellow nutgrass, the burrow not being longer than three or four 

 times the length of a larva. In this burrow, it makes for itself 

 a similar but larger elliptical cell of the burrowings and pupates 

 therein. 



The beetles travel on foot, although the power of resistance 

 to drowning is very great. Twenty-four adults of 5'. z'ci'atiis were 

 completely submerged in water for different periods of time, up to 

 seventeen hours and were found to suffer no harm. From this, it 

 may be inferred that if high water occurs at the proper time, it is 

 quite possible for many adults to be carried long distances and 

 infest a new field of sedge farther down the river. 



Food Plants. 



Practically all of the Sphenophori feed naturally upon some 

 one or more species of Scripus although other plants are often 

 attacked. Such is the case with S. vcnatus and 5". ::cac. Both 

 species pass their entire life history in association with the yellow 

 nut grass, but when sprouting corn, wheat or timothy is near by, 

 it is very likely to be attacked and, in fact, the adults prefer the 

 corn to the native food. Leaves of Cypcnis csculcntns containing 

 holes in rows were very similar to those of corn. Generally speak- 

 ing, grass crops that are not too far from Scripus are subject to 

 attack. Under artificial conditions, it was found that the adult 

 beetles will feed upon several other plants as. for example, S. 

 venatiis will feed upon potato leaf and stem, leaves and stem of 

 fox-tail or wild barley, crown and flower of dandelion, timothy, 

 oats, wdieat, corn, and yellow nutgrass. but showing preferences 

 for yellow nutgrass. corn, wheat, oats, and timothy. Pepper grass, 

 sw^eet clover, wnld lettuce, milkweed, horsew^eed, ragweed, hayweed 



