Stinging Insects 
37 
like sting palpi. Comparative morphological as well as embryologi- 
cal studies have clearly established that these three parts corres¬ 
pond to the three pairs of 
gonopophyses of the ovipositor 
of more generalized insects. 
An examination of the inter¬ 
nal structures (fig. 26) reveals 
two distinct types of poison 
glands, the acid-secreting and 
the alkaline-secreting glands, 
25. Sting of a honey bee. Psn Sc, base of acid 
and a prominent poison reser- poison gland; B Cl. alkaline poison gland; 
. T , I*.* ,1 • Stn Pip, sting palpi; Sh B, bulb of sting; 
VOir. in addition, there IS a Sh a, basal arm; Let, lancets or darts; Sh s, 
,, . . shaft of sting. Modified from Snodgrass. 
small pair of accessory struct¬ 
ures which have been called lubricating glands, on account of the 
supposed function of their product. The acid-secreting gland empties 
into the distal end of the poison reservoir which in turn pours the 
secretion into the muscular bulb-like enlargement at the base of the 
shaft. The alkaline secreting gland empties into the bulb ventrad 
of the narrow neck of the reservoir. 
The poison is usually referred to as formic acid. That it is not so 
easily explained has been repeatedly shown and is evidenced by the 
presence of the two types of glands. Carlet maintains that the pro¬ 
duct of either gland is in itself innocent, 
—it is only when they are combined that 
the toxic properties appear. 
The most detailed study of the poison 
of the honey-bee is that of Josef Langer 
(1897), who in the course of his work used 
some 25,000 bees. Various methods of 
obtaining the active poison for experi¬ 
mental purposes were used. For obtaining 
the pure secretion, bees were held in the 
fingers and compressed until the sting was 
exserted, when a clear drop of the poison 
was visible at its tip. This was then taken 
up in a capillary tube or dilute solutions 
bee. Modified from Snod- obtained by dipping the tip of the sting into 
a definite amount of distilled water. 
An aqueous solution of the poison was more readily obtained by 
pulling out the sting and poison sacs by means of forceps, and grinding 
