ii2 THE EMBRYOLOGY OF THE HONEY BEE 



The embryos of nearly all insects, as is well known, display at 

 some time during development more or less evident rudiments 

 of appendages on the ventral surface of the abdomen, as shown 

 in figure 36. Those on the first segment of the abdomen are fre- 

 quently very conspicuous and may, before the close of develop- 

 ment, attain quite a considerable size, as in Melolontha (Graber 

 1890). Biitschli (1870) has described rudiments of appendages 

 on all of the abdominal segments of the embryo of the honey 

 bee, the last two being especially conspicuous. "The three thor- 

 acic segments are provided with short appendages projecting 

 laterally and posteriorly, and by careful observation of the follow- 

 ing trunk segments a similar but very ill-defined process may be 

 observed on all of them; in the twelfth and thirteenth segments 

 these appendages are so much developed that they can be designa- 

 ted as the anal appendages" (p. 537). Biitschli's statements 

 however, are not well supported by his figures, since these do 

 not show the abdominal appendages with sufficient definiteness to 

 be convincing, with the exception of the last two, belonging to the 

 ninth and tenth abdominal segments. These are quite definitely 

 shown. Grassi (1884) apparently did not see the less well defined 

 abdominal appendages described by his predecessor, but states that 

 in several instances he saw two pairs of processes near the hinder 

 end of the embryo, at a stage when the rudiments of the mouth 

 parts had scarcely made their appearance. In Grassi's drawings 

 (Tab. IV Fig. 10) these processes have much the appearance of 

 artefacts, and his statement that these appendages frequently 

 could not be seen, lends probability to this assumption. The 

 writer was never successful in finding anything which could be 

 safely construed as abdominal appendages. They certainly occur, 

 nevertheless, in certain Hymenoptera. Carriere (1890) observed 

 unmistakable rudimentary appendages on the first and second seg- 

 ments of the. abdomen, and indications of them on the third and 

 fourth segments. All of these soon vanish. The embryo of Hylo- 

 toma (Graber, 1890) possesses twelve pairs of well defined abdom- 

 inal appendages, but this is to be expected, since Hylotoma is a 

 much more generalized form than Apis or Chalicodoma. Both 

 Wheeler (1910) and Tanquary (1913) report finding rudimentary 

 appendages on the abdominal segments of ant embryos. 



