Myrmeleon formicarius (Linnaeus, 1767)

The imago of M. formicarius is the largest neuropteran in Denmark with a forewing length of 35–40 mm (Figure 3 (a)). In addition to differing from M. bore in length, the wings are also wider, and M. formicarius can also be identified by its bright and broad spots on the pronotum (Figure 3 (b)), which are clearer and more distinct than those on M. bore (Nielsen, 2015).

The dark brown larva has spots on the hind coxa and femora; it is the only antlion species in northern Europe with this trait. Furthermore, the larva is equipped with dolichasters between the base and first tooth of the mandibles. The ventral side of the head is pale, covered by several dark spots, and a pair of significantly larger spots. The larva has four-segmented labial palps. The distal half of the 8th abdominal sternite segment is similar to M. bore, being covered by only short, black spines and without setae. The 3rd instar of the larva is considerably larger than that of the other species in Denmark (Friheden 1973; Badano and Pantaleoni 2014; Nielsen 2015).