BIOIvOGY^ EXPEJRIMENTAI. — DAVENPORT. I03 



what mitigated in the future by the experience which has been gained 

 and the more favorable temperature and arrangement in the new 

 vivarium. Although the difficulties are such that it is generally necessary 

 to start several pairs to rear progeny to maturity from one, the especial 

 advantages of this material as shown in the last report have led to satis- 

 factory results. 



In addition to lady-beetles, I have undertaken similar work in another 

 section of the Coccinellidse, viz, the squash-beetles. Although less favor- 

 able from the fact that there are but three species in the United States, 

 the ease with which large series are raised and the variation of its color 

 pattern make it desirable for some lines of work. 



In order to ascertain if the laboratory conditions would in themselves 

 produce modifications, pedigrees were started from normal specimens 

 of our local species of lady-beetles. With one exception, to be pursued 

 further, there has been no change. 



Normal specimens of other species from distant localities have been 

 bred, in one case for several generations. No modification has resulted. 

 Adalia frigida var. ophthahnica, from Springfield, Mass., produced some 

 progeny of the varieties disjuncta, ornatella, and annectans, but these were 

 probably predetermined. 



Attempts have been made to modify most of the species available by 

 increased dryness, moisture, heat, and cold. In contrast to the usual 

 negative results is the effect of cold applied intermittently to Hippodamia 

 convergens. The effect is an increase of the black markings along definite 

 lines, particular spots being prolonged in definite directions in a definite 

 order. Heat was effective only in the case of the squash-beetle, in which 

 the pattern of the wing-cover remains normal; but the black markings 

 of the thorax are all reduced, producing the conditions found in specimens 

 from Texas. 



Hybrid pedigrees have been started in the following cases : Hippodamia 

 convergens X H. c. var. amhigua;'^ Hippodamia convergens X H. c. var. 

 exterisa;"^ Hippodamia convergens X H. c. var. juncta;* Adalia frigida 

 var. ophthalmica* yi A. f. var. disjuncta;* Coccinella novemnotata X C. n. 

 var. confluens; and between various unnamed forms of Bpilachna borealis 

 and Hippodamia convergens. In general it may be said that the inheritance 

 is alternative in some cases, and in other cases some of the progeny are 

 intermediate. A Mendelian segregation is found in subsequent genera- 

 tions in some cases, but so far these have shown some individuals with 

 the parental characteristics modified. 



The following closely allied species and others less allied were inter- 

 sterile : Hippodamia convergens X H. glacialis; Coccinella calif ornica X C. 

 monticola. 



* Considered species by Casey. 



