107 



down into the stem, and its work is thus likely to be confused with 

 that of the bollworm. Various cutworms at times attack corn in a 

 way which, in the absence of the culprit, would suggest bollworm 

 injury. 



PREDACEOUS ENEMIES. 



PREDACEOUS ENEMIES OF THE EGGS AND YOUNG LARV^. 



The exposed position in which the eggs are placed lays them open 

 to attack by numerous insect enemies, although the fact that they are 

 scattered promiscuously about on the plants no doubt prevents much 

 wholesale destruction which might otherwise take place. 



The nymphs and adults of Triphleps 

 insidiosus Say (see fig. 13) have been 

 repeatedly observed feeding on bollworm 

 eggs and on very small larvae. This little 

 heteropteron is especiall}^ abundant in 

 fresh corn silk, and is often seen fre- 

 quenting cotton plants also. Although 

 in a number of instances noticed in the 

 laboratory they seem loath to attack 

 living larvse, they are sometimes to be fig. is.—Triphieps mskUosus: aduit 

 seen in the field with newly hatched and nymph (original). 



larvae impaled on their slender beaks. Their principal value lies, 

 however, in the large number of eggs which they destroy. A special 

 count was made at Sulphur Springs, Tex., on August 16, 1904, to 

 determine the probable proportion of eggs destroyed b}^ this agency. 

 The eggs on ten different silking ears were examined, and on an aver- 

 age 55 per cent of the eggs were found to be shriveled. It is probable 

 that most of these shriveled eggs had been punctured and their con- 

 tents sucked out by the Triphleps, which were numerous on the silks 

 at that time. This is no doubt an exceptional case, but it serves to 

 show of what great value the Triphleps may be under favorable 

 conditions. 



Larvae of the coccinellid beetle Megilla maculata DeG. , were observed 

 on several occasions feeding upon bollworm eggs, and they probably 

 do so very generally, especially on corn, where Megilla is quite abun- 

 dant. In feeding they often tear the ^g^ from its support, eat out the 

 contents, and cast aside the empty shell. The ladybird larvae can not 

 cope with bollworms which are their equal in size, but no doubt often 

 feed upon those newly hatched if eggs are scarce. While no other 

 species were observed to feed on bollworm eggs or larvae, it is not 

 improbable that others do. Figure 11 illustrates a common form in 

 cotton fields, feeding on plant lice and possibly on other insects. 



